feat: add popover opt-out configuration for loading indicator

[platosha]

Fixes #24072
Depends on vaadin/flow-hilla-common#26

• Add Popover opt-out property with default value (false)
• Implement listener for popover opt-out changes
• Update ConfigurationMap to support the new setting
• Add getter/setter methods in LoadingIndicatorConfiguration.java
• Include test cases for popover opt-out functionality

[github-actions]

Format Checker Report

There are 3 files with format errors

• To see a complete report of formatting issues, download the differences artifact

• To fix the build, please run mvn spotless:apply in your branch and commit the changes.

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  mvn spotless:apply
  

Here is the list of files with format issues in your PR:

flow-client/src/main/java/com/vaadin/client/communication/LoadingIndicatorConfigurator.java
flow-server/src/main/java/com/vaadin/flow/component/page/LoadingIndicatorConfiguration.java
flow-server/src/test/java/com/vaadin/flow/internal/nodefeature/LoadingIndicatorConfigurationMapTest.java

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Test Results

 1 410 files  ±0   1 410 suites  ±0   1h 18m 26s ⏱️ - 1m 29s
10 161 tests +1  10 092 ✅ +1  69 💤 ±0  0 ❌ ±0 
10 636 runs  +1  10 565 ✅ +1  71 💤 ±0  0 ❌ ±0 

Results for commit 9ad63ee. ± Comparison against base commit 3697241.