fix(dashboards): stricter permission check when dashboards cover all/my projects

[oioki]

When Open Membership is disabled, it is expected to have more granular access to certain objects that are associated with projects. First version of project-level access on dashboards was implemented in https://github.com/getsentry/sentry/pull/70228

However, dashboards that cover "All Projects" or "My Projects" do not have explicit project ids, therefore we need to do a different check. After this PR, we will allow access to such dashboards only in these cases:

• if Open Membership is enabled;
• if actor is a Manager/Owner (having org:write scope);
• if actor is the original creator of a dashboard.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.

:white_check_mark: All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...rc/sentry/api/endpoints/organization_dashboards.py	77.77%	1 Missing and 1 partial :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #78615      +/-   ##
==========================================
- Coverage   78.14%   78.14%   -0.01%     
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  Files        7099     7100       +1     
  Lines      312836   312695     -141     
  Branches    51085    51072      -13     
==========================================
- Hits       244481   244364     -117     
+ Misses      61975    61963      -12     
+ Partials     6380     6368      -12