How to reproduce:
1. Create a new Unity version with the version that doesn't have the Web Module installed
2. Go to Window -> Package Management -> Package Manager (Window -> Package Manager) -> Unity Registry 
3. Find and Install the "WebGL Publisher" package
4. Go to Publish -> WebGL Project -> Get Started
5. Go to the Unity Hub and install the "WebGL Build Support" module without closing the project
6. Return to the "Publish" window and click "Build and Publish" -> Switch to WebGL
7. Observe the results

Expected results: The build succeeds or the "Publish" window asks to restart the project
Actual results: The build fails with "UnityException: Build target 'WebGL' not supported" error

Reproducible with: 6000.0.39f1, 6000.1.0b7, 6000.2.0a4

Reproducible on: Windows 11 Pro
Not reproducible on: No other environment tested

Notes:
- "Build" window doesn't allow switching to the WebGL without restarting the project
- Restarting the project fixes the issue