fix: Patch mime sniffer for html utf8 bom, svg and xml files OS-16547

[t-bashir-bs]

Description of Change

This change cherry picks change IDs from QtWebEngine.

• I11c9915a4c23155fc8b8b4e405b69ed48821db5a
• I7ee3558529c24a08b22b1ad3a4a9d6df73174cdd
• I6d9a40bb65b8ff4d44e4e5b6d850f1a728768feb

These patch the mime sniffer to allow it to handle html files with utf8 bom, recognise svg files and allow for comments in xml files.
It includes an additional change not in the QtWebEngine version to stop the binary sniffer changing the mime type of text/xml files to text/plain.
Change includes new test cases.

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• relevant documentation, tutorials, templates and examples are changed or added
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes:

[caneraltinbasak]

Is this ready, or would you like to have your CSS sniff fix in this changeset?

[t-bashir-bs]

Is this ready, or would you like to have your CSS sniff fix in this changeset?

Its ready. The CSS issue (when I finally find the cause) will likely will mean patching some other file and I think is different enough to be in a different changeset.