federate with allowed hosts instead of blocking them

[boringcactus]

What

There is a bug in #14643 where new federated hosts are added to the blockedHosts instead of the federatedHosts.

Why

When I add federated hosts, I want to federate with them and not to block them.

Additional info (optional)

Checklist

• Read the contribution guide
• Test working in a local environment
• (If needed) Add story of storybook
• (If needed) Update CHANGELOG.md
• (If possible) Add tests

[KisaragiEffective]

Duplicate of #14662, I'm sorry!

[github-actions]

このPRによるapi.jsonの差分
差分はありません。
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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 39.79%. Comparing base (a3d236c) to head (b9c0b26).
Report is 209 commits behind head on develop.

Files with missing lines	Patch %	Lines
...kend/src/server/api/endpoints/admin/update-meta.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #14671      +/-   ##
===========================================
- Coverage    41.74%   39.79%   -1.96%     
===========================================
  Files         1549     1545       -4     
  Lines       196555   193742    -2813     
  Branches      2767     3591     +824     
===========================================
- Hits         82055    77100    -4955     
- Misses      113939   116079    +2140     
- Partials       561      563       +2     

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