Remove unnecessary test on GitHub Actions

- Remove Java 11 test on GitHub Actions
as UAA will no longer be built with Java 11 after this PR

[#186054019]

.github/workflows/gradle.yml

@@ -6,7 +6,7 @@ on:
   pull_request:
     branches: [ develop ]
 
-# Run job on CF landscape, e.g. ubuntu 1804 and bellsoft java 11
+# Run job on CF landscape, e.g. ubuntu 1804 and bellsoft java 17
 permissions:
   contents: read
 
@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [ '11', '17' ]
+        java: [ '17' ]
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-java@v3