Improve VTOrc startup flow

[GuptaManan100]

Description

This PR makes the changes requested in #15314.

This PR removes the wait period from VTOrc. Also, I noticed that the topo tick that we use to load all the information doesn't trigger immediately. So, in this PR, during the starting phase of VTOrc, we make it populate all the information once in the beginning. And then we can start checking and recovering failures without needing the wait period we had before.

An additional benefit of the changes in this PR is that when VTOrc displays itself as healthy in the /debug/healthy API, then it is actually ready to run recoveries, which wasn't true before.

Related Issue(s)

• Fixes Feature Request: Refactor how VTOrc starts up #15314

Checklist

• "Backport to:" labels have been added if this change should be back-ported to release branches
• If this change is to be back-ported to previous releases, a justification is included in the PR description
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on CI?
• Documentation was added or is not required

Deployment Notes

[vitess-bot]

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[GuptaManan100]

I fixed this too because it was really just 1 line fix, involving adding ts.Close() to closeVTOrc

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (27be916) 67.53% compared to head (62f42e2) 67.62%.
Report is 4 commits behind head on main.

Files	Patch %	Lines
go/vt/vtorc/logic/vtorc.go	81.25%	3 Missing ⚠️
go/vt/vtorc/logic/tablet_discovery.go	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #15315      +/-   ##
==========================================
+ Coverage   67.53%   67.62%   +0.08%     
==========================================
  Files        1561     1561              
  Lines      193387   193392       +5     
==========================================
+ Hits       130607   130778     +171     
+ Misses      62780    62614     -166     

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