fix: fix panel header icon texture check

[Flyga-M]

Fixes a potential crash, where the AsyncTexture2D Panel._icon is not null, but it's internal AsyncTexture2D._activeTexture2D is null.

This may happen if

• the AsyncTexture2D is instantiated like new AsyncTexture2D(null)
• AsyncTexture2D.SwapTexture(Texture2D) is called like SwapTexture(null)

Discussion Reference

All new features must be discussed prior to code review. This is to ensure that the implementation aligns with other design considerations. Please link to the Discord discussion:

PM discussion

Is this a breaking change?

Breaking changes require additional review prior to merging. If you answer yes, please explain what breaking changes have been made.

No

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[dlamkins]

Thank you!