QImage svg plugin claims to support any gzipped content

Creating QImageReader with a QBuffer containing any gzipped content will lead it to be read by the svg plugin: https://github.com/qt/qtsvg/blob/82909c05b7e2cab3eae86f4de4b562f06f090ea3/src/plugins/imageformats/svg/qsvgiohandler.cpp#L96

What in turn leads for the following warning to displayed (which is really annoying if application checks whether it can generate a preview for arbitrary data that way and processes a lot of data, that's what I observe): https://github.com/qt/qtsvg/blob/82909c05b7e2cab3eae86f4de4b562f06f090ea3/src/svg/qsvgtinydocument.cpp#L129

Moreover, this likely creates a problem that any other plugin won't be able to process gzipped data due to this:
https://github.com/qt/qtbase/blob/b05540bd00d051c74e67d138f5148eb23e018996/src/gui/image/qimagereader.cpp#L326-L331
https://github.com/qt/qtsvg/blob/82909c05b7e2cab3eae86f4de4b562f06f090ea3/src/plugins/imageformats/svg/main.cpp#L42

I believe it should try to partially decompress it to read those first 16 bytes before claiming it can read the data.