Share local file/dir using IPFS does not work on desktop

[spylogsster]

Second part of #15935
Not all cases were handled in last PR

Description + Steps to Reproduce

• Start node and try to import without IPNS keys

Actual result:

Nothing happens, no error in console

Expected result:

File/dir picker is opened

[stephendonner]

Verified PASSED using the testplan from #14770 (comment); see there for detailed steps of the below tests. Tested with build

Brave	1.27.10 Chromium: 91.0.4472.70 (Official Build) nightly (x86_64)
Revision	fe095368270a32c92959403754bf6fd357dd9953-refs/branch-heads/4472@{#1172}
OS	macOS Version 11.3.1 (Build 20E241)

Also confirmed:

• no crashes
• no IPFS-shared files appeared in either the "shelf" on the browser toolbar, or the Downloads window; just their original, downloaded sources, as expected

CNN (directory)	CNN (file)	Vincent Van Goh (file)	The Maltese Falcon (file)	Downloads window

CNN page's directory share link: https://dweb.link/ipfs/QmPThhLyadq1qfMp2ZDG3Qf8gCkCURuPgT9JuAGzUy3Hvq?filename=CNN+-+Breaking+News%2C+Latest+News+and+Videos_files

Vincent Van Goh page share link: https://bafybeiec4exjpqpkcoyh7eener6mhoeijhuj5es5qdz5dt7ei4y46knzty.ipfs.dweb.link/?filename=Vincent+van+Gogh+-+Wikipedia.html

The Maltese Falcon file share link: https://bafybeiepa2nep2hips6xlphsj6fg4uuxa2eicq4o3rkfke7njyo5veyc4a.ipfs.dweb.link/QmNbBjvpPRL7WwCorwCCawnjNCFDuWBBAr3rJWq1G3musS

[kjozwiak]

Going to remove the QA Pass-macOS as the above was checked on Nightly so brave/brave-core#8901 can be uplifted. Thanks for running through the above on a Friday night @StephenBass 👍

[stephendonner]

Verified PASSED using the testplan from #14770 (comment) with build

Brave	1.26.43 Chromium: 91.0.4472.77 (Official Build) beta (x86_64)
Revision	1cecd5c8a856bc2a5adda436e7b84d8d21b339b6-refs/branch-heads/4472@{#1246}
OS	macOS Version 11.4 (Build 20F71)

CNN dir	CNN file	Maltese Falcon video	Vincent Van Gogh page	Downloads window	brave-imports dir

Confirmed the following:

• all imports worked, without errors
• file content was intact
• no crashes while downloading/importing/loading
• no IPFS-shared files appeared in either the "shelf" on the browser toolbar, or the Downloads window; just their original, downloaded sources, as expected