Gradle : gradle.properties on [root] : Changes are not detected

### Apache NetBeans version

Apache NetBeans 15

### What happened

We have a gradle main project with subprojects. Some sub projects have an extra source set which is defined based on a property set in gradle.properties in the root folder.

In Netbeans 14, if we changed the gradle.properties file, Netbeans detected the change and reloaded all the required sub projects.
In Netbeans 15 , this doesn't happen anymore.

I have deleted the cache of NB15, and now even if I reload manually the project, the incorrect source folder is visible in the project tree.

### How to reproduce

_No response_

### Did this work correctly in an earlier version?

Apache NetBeans 14

### Operating System

Windows 10

### JDK

JDK 11

### Apache NetBeans packaging

Apache NetBeans provided installer

### Anything else

_No response_

### Are you willing to submit a pull request?

No

### Code of Conduct

Yes

Start by reproducing the issue in Apache NetBeans 15 on Windows 10 with a Gradle main project, subprojects, and a root gradle.properties value that controls an extra source set. Compare edits and reload behavior with NetBeans 14; done means changing the root property reloads the required subprojects and updates the source folder shown in the project tree.

Written by the indexing model from the issue text.