add setting to configure when to raise the user unload event and remove user always before requesting sign-out

[pamapa]

Closes/fixes #1379

Checklist

• This PR makes changes to the public API
• I have included links for closing relevant issue numbers

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (2a69f62) 79.78% compared to head (2f06982) 79.83%.

Files	Patch %	Lines
src/UserManagerEvents.ts	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1391      +/-   ##
==========================================
+ Coverage   79.78%   79.83%   +0.05%     
==========================================
  Files          45       45              
  Lines        1731     1741      +10     
  Branches      344      348       +4     
==========================================
+ Hits         1381     1390       +9     
- Misses        312      313       +1     
  Partials       38       38              

Flag	Coverage Δ
unittests	79.83% <93.33%> (+0.05%)	⬆️

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[pamapa]

@PSanetra Can you review and test?

• unload event is
  • deferred to callback (default, raiserUserUnloadEventBeforeSignoutRequest=false)
  • done before requesting the sign-out (option: raiserUserUnloadEventBeforeSignoutRequest=true)
• remove user from storage is always (independent of option) done before requesting the sign-out

Any better name for raiserUserUnloadEventBeforeSignoutRequest?

[pamapa]

maybe we should just call await this._removeUser(true) here, it should not hurt and is simpler (less code)

[PSanetra]

I think this should be ok as a signed in user would be unexpected in any case, right?

[PSanetra]

I think raiserUserUnloadEventBeforeSignoutRequest might be renamed to noSignoutCallbacksSupported or signoutCallbackSupported with true as default if the value is undefined.

The user/ developer is expected to set signoutCallbackSupported to false if he expects never to call any signout callback.

[pamapa]

I think this solution is too complicated, i do not like an option for this at all. The previous behavior (<v3.0) was dead simple