fix: do not suppress external project ID determination errors (#1153)

Do not suppress the underlying error, as the error could contain helpful
information for debugging and fixing. This is especially true for
external account creds as in order to get the project ID, the following
operations have to succeed:
1. Valid credentials file should be supplied.
2. Ability to retrieve access tokens from STS token exchange API.
3. Ability to exchange for service account impersonated credentials (if
   enabled).
4. Ability to get project info using the access token from step 2 or 3.

Without surfacing the error, it is harder for developers to determine
which step went wrong.

src/auth/googleauth.ts

@@ -671,11 +671,18 @@ export class GoogleAuth {
       return null;
     }
     const creds = await this.getClient();
-    try {
-      return await (creds as BaseExternalAccountClient).getProjectId();
-    } catch (e) {
-      return null;
-    }
+    // Do not suppress the underlying error, as the error could contain helpful
+    // information for debugging and fixing. This is especially true for
+    // external account creds as in order to get the project ID, the following
+    // operations have to succeed:
+    // 1. Valid credentials file should be supplied.
+    // 2. Ability to retrieve access tokens from STS token exchange API.
+    // 3. Ability to exchange for service account impersonated credentials (if
+    //    enabled).
+    // 4. Ability to get project info using the access token from step 2 or 3.
+    // Without surfacing the error, it is harder for developers to determine
+    // which step went wrong.
+    return await (creds as BaseExternalAccountClient).getProjectId();
   }
 
   /**

test/test.googleauth.ts

@@ -1968,7 +1968,7 @@ describe('googleauth', () => {
 
           await assert.rejects(
             auth.getProjectId(),
-            /Unable to detect a Project Id in the current environment/
+            /The caller does not have permission/
           );
           scopes.forEach(s => s.done());
         });
@@ -1980,7 +1980,7 @@ describe('googleauth', () => {
 
           await assert.rejects(
             auth.getProjectId(),
-            /Unable to detect a Project Id in the current environment/
+            /The file at invalid does not exist, or it is not a file/
           );
         });