import bookmarks doesn't have extension option with html

[LaurenWags]

Description

Per (second) test case c 'Import bookmark from HTML' from #11906 - when importing bookmarks from HTML file the dialog should have an extension option with html

Steps to Reproduce

1. Menu->Bookmarks->Import Browser Data.. and select HTML file
2. The default path should be your download path

Actual result:
The dialog does not have an extension option with html.

Expected result:
The dialog should have extension option with html and the default extension should be html

Reproduces how often:
Easily

Brave Version

about:brave info:
Brave | 0.21.654
V8 | 6.5.254.26
rev | bc6272c
Muon | 5.1.3
OS Release | 16.7.0
Update Channel | Beta
OS Architecture | x64
OS Platform | macOS
Node.js | 7.9.0
Brave Sync | v1.4.2
libchromiumcontent | 65.0.3325.88

Reproducible on current live release:
Yes

Additional Information

[bsclifton]

If I hit the Options button in the bottom left (macOS):

It shows the extension (as expected):

On Windows, it works as expected:

@darkdh is this expected behavior? (having to click Options in order to see the extension that is being filtered). The filter itself is working, you just need to click Options to show it

[darkdh]

yes, please click on Options and you can't choose files other than html. so this is correct behavior