Correct conditional logic for publishing steps of build workflow

The "Arduino IDE" GitHub Actions workflow is used to generate several distinct types of builds:

- Tester builds of commits
- Nightly builds
- Release builds

Different actions must be performed depending on which type of build is being produced. The workflow uses dedicated jobs
for publishing the nightly builds and for publishing the release builds. Those jobs are configured to run only when
certain criteria are met.

One such criteria is that the merge-channel-files job ran as expected. There are four possible result types of a job,
which should be handled as follows:

| Result   | Run dependent job? |
| -------- | ------------------ |
| success  | Yes                |
| failure  | No                 |
| canceled | No                 |
| skipped  | Yes                |

GitHub Actions automatically takes the desired action regarding whether the dependent job should run for the first three
result types, but that is not the case for the "skipped" result. The merge-channel-files job dependency is skipped when
a channel file merge is not needed and so this is not cause to cancel the build publishing.

The only way to make a dependent job run when the dependency was skipped is to add the `always()` expression to the job
conditional. This goes too far in the other direction by causing the job to run even when the dependency failed or was
canceled. So it is necessary to also add logic for each of the dependency job result types to the conditional, which
makes it quite complex when combined with the logic for the other criteria of the job.

In order to reduce the amount of complexity of the conditionals of the dependent jobs, a job was interposed in the
dependency chain, which was intended to act simply as a container for the logic about the merge-channel-files job
result. Unfortunately it turns out that even if the direct dependency job's result was success, if any ancestor in the
dependency chain was skipped, GitHub Actions still skips all dependent jobs without an `always()` expression in their
conditional, meaning the intermediate job was pointless. This caused the build publishing jobs to be skipped under the
conditions where they should have ran.

The pointless intermediate job is hereby removed, an `always()` expression added to the conditionals of the dependent
jobs, and the full logic for how to handle each dependent job result type added there as well.

Author: per1234

Diff for: .github/workflows/build.yml

@@ -452,24 +452,6 @@ jobs:
           name: ${{ env.JOB_TRANSFER_ARTIFACT }}
           path: ${{ env.CHANNEL_FILES_PATH }}
 
-  # This job serves only as a container for the logic necessary to allow dependent jobs to run if the
-  # merge-channel-files job was skipped.
-  merge-channel-files-complete:
-    needs:
-      - merge-channel-files
-    if: >
-      always() &&
-      (
-        needs.merge-channel-files.result == 'skipped' ||
-        needs.merge-channel-files.result == 'success'
-      )
-    runs-on: ubuntu-latest
-    permissions: {}
-    steps:
-      # GitHub Actions requires every job to have >=1 step.
-      - name: Dummy step
-        run: ''
-
   artifacts:
     name: ${{ matrix.artifact.name }} artifact
     needs:
@@ -546,9 +528,16 @@ jobs:
   publish:
     needs:
       - build-type-determination
-      - merge-channel-files-complete
+      - merge-channel-files
       - changelog
     if: >
+      always() &&
+      needs.build-type-determination.result == 'success' &&
+      (
+        needs.merge-channel-files.result == 'skipped' ||
+        needs.merge-channel-files.result == 'success'
+      ) &&
+      needs.changelog.result == 'success' &&
       needs.build-type-determination.outputs.publish-to-s3 == 'true' &&
       needs.build-type-determination.outputs.is-nightly == 'true'
     runs-on: ubuntu-latest
@@ -572,9 +561,17 @@ jobs:
   release:
     needs:
       - build-type-determination
-      - merge-channel-files-complete
+      - merge-channel-files
       - changelog
-    if: needs.build-type-determination.outputs.is-release == 'true'
+    if: >
+      always() &&
+      needs.build-type-determination.result == 'success' &&
+      (
+        needs.merge-channel-files.result == 'skipped' ||
+        needs.merge-channel-files.result == 'success'
+      ) &&
+      needs.changelog.result == 'success' &&
+      needs.build-type-determination.outputs.is-release == 'true'
     runs-on: ubuntu-latest
     steps:
       - name: Download [GitHub Actions]