Fix invitation acceptance logic and update permission constant naming

[SammyOina]

What type of PR is this?

What does this do?

• Refactor
  • Enhanced the invitation acceptance flow with improved validation and authorization checks for a more secure process.
• Style
  • Updated permission naming to adhere to consistent coding standards.

Which issue(s) does this PR fix/relate to?

• Related Issue #
• Resolves BUG: Missing critical middleware checks when adding user via invitation #2802

Have you included tests for your changes?

Did you document any new/modified feature?

Notes

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 8 lines in your changes missing coverage. Please review.

Project coverage is 28.28%. Comparing base (af8caa4) to head (8437624).

Files with missing lines	Patch %	Lines
domains/middleware/authorization.go	0.00%	7 Missing ⚠️
domains/roleoperations.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2803      +/-   ##
==========================================
+ Coverage   27.55%   28.28%   +0.73%     
==========================================
  Files         351       30     -321     
  Lines       55347     5462   -49885     
==========================================
- Hits        15251     1545   -13706     
+ Misses      39340     3822   -35518     
+ Partials      756       95     -661     

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[arvindh123]

Does this operations is needed some where else ? Why it is exported ?

[SammyOina]

here

if err := am.extAuthorize(ctx, auth.EncodeDomainUserID(domainID, inv.InvitedBy), domains.AddRoleUsersPermission, policies.DomainType, domainID); err == nil {
		return err
	}
	```

[dborovcanin]

@SammyOina Please rebase.

[dborovcanin]

@SammyOina Please rebase. @arvindh123 Please review.