Import file schemes correctly

[spylogsster]

Resolves brave/brave-browser#16705

• Import local files video/audio/images via file:/// scheme

Submitter Checklist:

• I confirm that no security/privacy review is needed, or that I have requested one
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally: npm run test -- brave_browser_tests, npm run test -- brave_unit_tests, npm run lint, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

1. Clean profile 1.27.x
2. Enable IPFS
3. Use the Ctlr+O shortcut key and open any MP4 file from your local machine
4. Right-click on the play icon and select Import to IPFS->Selected video option
5. Getting IPFS import failed

[mkarolin]

++

[stephendonner]

Verified FIXED using the testplan above with build

Brave	1.28.64 Chromium: 92.0.4515.81 (Official Build) nightly (x86_64)
Revision	dba3af0a9a48954c8b188bc641e651580b7cb7b5-refs/branch-heads/4515@{#1162}
OS	macOS Version 11.4 (Build 20F71)

Steps:

1. clean profile
2. loaded ipns://brantly.eth and clicked on Use a local node
3. used Ctlr+O shortcut key and opened sample-5s.mp4 from my local machine
4. right-clicked on the play icon and selected Import to IPFS->Selected video option

• Confirmed I got an alert notification letting me know the import had completed successfully, with a shareable link https://dweb.link/ipfs/QmYog8dP2hJpgQXvfFes6CfhT64fgzoksG4K3CPAt3PMFC?filename=sample-5s.mp4
• Confirmed the file was copied into brave-imports
• Confirmed the file was playable and intact

example	example	example	example

@spylogsster @bbondy I think this one is upliftable, given the fix is relatively small in size and scope; thoughts?