CI: exclude all Bitmap tests on non-Windows (not just BitmapWithAlphaTests)

BitmapExtensionsTests also uses System.Drawing.Common which requires
Windows GDI+. MSTest treats Assert.Inconclusive in [ClassInitialize]
as test failures, not skips — so the runtime guard doesn't help CI.

Broaden the extra_filter from FullyQualifiedName!~BitmapWithAlphaTests
to FullyQualifiedName!~Bitmap to exclude all Bitmap test classes
(BitmapExtensionsTests, BitmapWithAlphaTests, OpenBugsBitmap) on
non-Windows runners.

Author: Nucs

.github/workflows/build-and-release.yml

@@ -49,9 +49,9 @@ jobs:
           - os: windows-latest
             extra_filter: ''
           - os: ubuntu-latest
-            extra_filter: '& FullyQualifiedName!~BitmapWithAlphaTests'
+            extra_filter: '& FullyQualifiedName!~Bitmap'
           - os: macos-latest
-            extra_filter: '& FullyQualifiedName!~BitmapWithAlphaTests'
+            extra_filter: '& FullyQualifiedName!~Bitmap'
 
     runs-on: ${{ matrix.os }}