fix(gatsby): print real plugin loading error in verbose (#27664)

* fix(gatsby): print real plugin loading error in verbose

* Use the reporter

* Check for verbose

Author: pvdz

packages/gatsby/src/bootstrap/load-plugins/load.ts

@@ -17,6 +17,7 @@ import {
   ISiteConfig,
 } from "./types"
 import { PackageJson } from "../../.."
+import reporter from "gatsby-cli/lib/reporter"
 
 function createFileContentHash(root: string, globPattern: string): string {
   const hash = crypto.createHash(`md5`)
@@ -118,9 +119,17 @@ export function resolvePlugin(
       version: packageJSON.version,
     }
   } catch (err) {
-    throw new Error(
-      `Unable to find plugin "${pluginName}". Perhaps you need to install its package?`
-    )
+    if (process.env.gatsby_log_level === `verbose`) {
+      reporter.panicOnBuild(
+        `plugin "${pluginName} threw the following error:\n`,
+        err
+      )
+    } else {
+      reporter.panicOnBuild(
+        `There was a problem loading plugin "${pluginName}". Perhaps you need to install its package?\nUse --verbose to see actual error.`
+      )
+    }
+    throw new Error(`unreachable`)
   }
 }