removed MIME file tests (#19951)

* removed MIME file tests
see also 0f7248c#commitcomment-127223170

* added CHANGELOG line

Author: schmunk42

framework/CHANGELOG.md

@@ -6,6 +6,7 @@ Yii Framework 2 Change Log
 
 - Bug #19925: Improved PHP version check when handling MIME types (schmunk42)
 - Bug #19940: File Log writer without newline (terabytesoftw)
+- Bug #19951: Removed unneeded MIME file tests (schmunk42)
 
 
 2.0.49 August 29, 2023