Fix: nullability issue with Bitmap on Android

[samipshresthaq]

Description

Fixes the following compile error when building the Android app.

DownloadMapImageTask.kt:80:56 Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type 'Bitmap?'.

Reproduced using

• @rnmapbox/maps version: 10.3.5
• React Native version: 0.87.0
• Gradle: 9.4.1

Screenshot OR Video

Verification

Verified that the app built successfully without any :rnmapbox_maps:compileDebugKotlin errors.

[mfazekas]

Superseded by #4297, which fixes the same nullable-bitmap compile error without the force-unwrap (avoids a possible NPE if the bitmap is ever actually null). Merged in e33400c. Thanks for the report and the fix.