Fix: #36065
The IamgeAnalyzer passes a image to ImageMagick without checking if the
image is supported by ImageMagick. This patch checks that image is
supported and if not logs an error and returns an empty hash instead of
raising an error. This is the same error handling we do when we
encounter a LoadError when mini_magick is not installed.
ImageAnalyzerTest and VideoAnalyzerTest are defining the same helper,
since both use `#create_file_blob` that is defined in TestHelper, it
makes sense to move `#extract_metadata_from` to that side.
Fixes analyzing an SVG image without an XML declaration. ImageMagick occasionally looks to the extension when it can't discern the type of an image file from its contents.
References #31356.
