Fleet UI: Managed account > Host details page modal + Activity feeds

[RachelElysia]

Issue

Closes #42946

Description

• Host details page work
• Activity feed work

Screen recording

Testing

• Added/updated automated tests
• QA'd all new/changed functionality manually

[codecov]

Codecov Report

❌ Patch coverage is 21.42857% with 55 lines in your changes missing coverage. Please review.
✅ Project coverage is 66.85%. Comparing base (0bf48d3) to head (8287e46).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...vityFeed/GlobalActivityItem/GlobalActivityItem.tsx	0.00%	26 Missing ⚠️
...modals/ManagedAccountModal/ManagedAccountModal.tsx	15.38%	11 Missing ⚠️
.../hosts/details/HostDetailsPage/HostDetailsPage.tsx	0.00%	8 Missing ⚠️
frontend/services/entities/hosts.ts	0.00%	3 Missing ⚠️
...ityItem/CreatedManagedLocalAccountActivityItem.tsx	33.33%	2 Missing ⚠️
...tivityItem/ReadManagedLocalAccountActivityItem.tsx	33.33%	2 Missing ⚠️
...RotatedManagedLocalAccountPasswordActivityItem.tsx	33.33%	2 Missing ⚠️
frontend/utilities/endpoints.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #43353      +/-   ##
==========================================
- Coverage   66.86%   66.85%   -0.02%     
==========================================
  Files        2586     2590       +4     
  Lines      207452   207522      +70     
  Branches     9284     9197      -87     
==========================================
+ Hits       138714   138729      +15     
- Misses      56111    56166      +55     
  Partials    12627    12627              

Flag	Coverage Δ
frontend	54.68% <21.42%> (-0.10%)	⬇️

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