gradle project failed when the frontend folder is in the project root

[ZheSun88]

Description of the bug

platform snapshot build failed with following error.

Execution failed for task ':vaadinBuildFrontend'. org.gradle.internal.UncheckedException: com.vaadin.flow.server.ExecutionFailedException: Discovered @Theme annotation with theme name 'gradle-test', but could not find the theme directory in the project or available as a jar dependency. Check if you forgot to create the folder under '/opt/agent/work/6776dee9e21843c0/vaadin-platform-gradle-test/./src/main/frontend/themes' or have mistyped the theme or folder name for 'gradle-test'.

based on the commit message, old project should still work after this change.

Expected behavior

project still work

Minimal reproducible example

https://bender.vaadin.com/buildConfiguration/VaadinPlatform_TestReleasePlatformSnapshotToMavenVaadinPrerelease/509911?expandBuildProblemsSection=true&hideProblemsFromDependencies=false&hideTestsFromDependencies=false

Versions

• Vaadin / Flow version: 24.4-SNAPSHOT
• Java version:
• OS version:
• Browser version (if applicable):
• Application Server (if applicable):
• IDE (if applicable):