CI: trigger circleci job on readthedocs-ext on merge (#10433)

Same as we do with readthedocs-corporate,
there was a bug that could have been caught with this.

Also, don't think we need to hide the repo and job name,
we have linked to those repos from public places already.

Author: stsewd

.github/workflows/main.yml

@@ -16,11 +16,20 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - name: Trigger tests in corporate
+    - name: Trigger tests in readthedocs-corporate
       run: |
         curl --request POST \
         --silent --output /dev/null \
-        --url https://circleci.com/api/v2/project/gh/${{ secrets.CORPORATE_REPO }}/pipeline \
+        --url https://circleci.com/api/v2/project/gh/readthedocs/readthedocs-corporate/pipeline \
         --user '${{ secrets.CIRCLECI_USER_TOKEN }}:' \
         --header 'content-type: application/json' \
-        --data '{"branch": "main", "parameters":{"CIRCLE_JOB": "${{ secrets.CIRCLECI_JOB }}"}}'
+        --data '{"branch": "main", "parameters":{"CIRCLE_JOB": "tests"}}'
+
+    - name: Trigger tests in readthedocs-ext
+      run: |
+        curl --request POST \
+        --silent --output /dev/null \
+        --url https:/circleci.com/api/v2/project/gh/readthedocs/readthedocs-ext/pipeline \
+        --user '${{ secrets.CIRCLECI_USER_TOKEN }}:' \
+        --header 'content-type: application/json' \
+        --data '{"branch": "main", "parameters":{"CIRCLE_JOB": "tests"}}'