Fix password generator close button for good

[droidmonkey]

• Avoids using QDialog which breaks the standalone password generator

Revert "Fix password dialog close button"

This reverts commit 5b47190.

Fixes #7952.

Testing strategy

Tested on Windows with latest browser extension

Type of change

• ✅ Bug fix (non-breaking change that fixes an issue)

[codecov]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (49f2924) 64.86% compared to head (35e38fb) 64.87%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #9743      +/-   ##
===========================================
+ Coverage    64.86%   64.87%   +0.01%     
===========================================
  Files          335      335              
  Lines        41066    41064       -2     
===========================================
+ Hits         26636    26638       +2     
+ Misses       14430    14426       -4     

Files	Coverage Δ
src/browser/BrowserService.h	100.00% <ø> (ø)
src/gui/PasswordGeneratorWidget.cpp	68.50% <0.00%> (-0.07%)	⬇️
src/browser/BrowserAction.cpp	10.21% <0.00%> (-0.05%)	⬇️
src/browser/BrowserService.cpp	25.17% <0.00%> (+0.08%)	⬆️

... and 5 files with indirect coverage changes

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[varjolintu]

This works ok, but I need to fix the messaging problems to the extension side.

[droidmonkey]

@varjolintu Which PR over on the browser side will fix the message issues?

[varjolintu]

@droidmonkey This one: keepassxreboot/keepassxc-browser#1961. I'd suggest you test it with multiple browsers.

I had to add a new boolean to keepass.js to prevent multiple simultaneous generate-password calls. This is not an issue in Chromium based browsers, but in Firefox native messaging does something differently and some messages are clearly left in the queue, which also causes BrowserHost's socket->readAll() call to return multiple messages, causing "garbage end of buffer" errors etc. And when a new generate-password is requested when the generator is already open, all those messages in the Firefox's internal buffer gets to KeePassXC.

This might cause Firefox to drop the accepted password if user manually requested the generator again. But in Chromium based browsers the password is filled normally even after multiple requests.

[droidmonkey]

@varjolintu I made substantial edits here, I think this makes the experience better and solves the issue using a QWidget. Major change includes raising an existing password generator dialog if the user didn't close it before.