Reduce RSpec/MultipleExpectations in media_attachment spec

[mjankowski]

Requirement of #29223

[codecov]

Codecov Report

Attention: 11 lines in your changes are missing coverage. Please review.

Comparison is base (86500e3) 85.01% compared to head (bd4bb79) 85.00%.
Report is 70 commits behind head on main.

Files	Patch %	Lines
app/lib/application_extension.rb	62.50%	3 Missing ⚠️
app/models/concerns/user/omniauthable.rb	85.00%	0 Missing and 3 partials ⚠️
app/controllers/api/v1/statuses_controller.rb	87.50%	0 Missing and 1 partial ⚠️
.../controllers/auth/omniauth_callbacks_controller.rb	66.66%	0 Missing and 1 partial ⚠️
app/controllers/auth/sessions_controller.rb	50.00%	0 Missing and 1 partial ⚠️
app/lib/signature_parser.rb	93.75%	0 Missing and 1 partial ⚠️
app/models/concerns/user/ldap_authenticable.rb	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #29228      +/-   ##
==========================================
- Coverage   85.01%   85.00%   -0.01%     
==========================================
  Files        1059     1060       +1     
  Lines       28277    28307      +30     
  Branches     4538     4539       +1     
==========================================
+ Hits        24040    24063      +23     
- Misses       3074     3078       +4     
- Partials     1163     1166       +3     

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