Auto merge of #25869 - iulianR:issue-23057-tinifiledialogs, r=jdm

Move tinyfiledialog call from script to embedder

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PR is based on work started in #23651. I rebased on top of master and addressed review comments. Handling the `PromptPermission` message in `libsimpleservo` is probably not ideal. Looking forward to make more changes, just let me know how I should proceed.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #23057 (GitHub issue number if applicable)

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Cargo.lock

@@ -4762,7 +4762,6 @@ dependencies = [
  "swapper",
  "tendril",
  "time",
- "tinyfiledialogs",
  "unicode-bidi",
  "unicode-segmentation",
  "url",