Improve error reporting from scale-in protection modification

[tevoinea]

Summary of the Pull Request

What is this about?

Return different error codes from the different failure modes of modifying scale-in protection on a VM instance. Closes #3183

Info on Pull Request

What does this include?

1. 4 new error codes that represent our known failure modes for modifying scale-in protection
2. Downgrade Upgrade Already In Progress errors to a warning
3. In the case of removing scale-in protection, downgrade Instance No Longer Exists to a warning

Validation Steps Performed

How does someone test & validate?

check-pr should not longer report errors in check logs for modifying scale-in protection

[codecov-commenter]

Codecov Report

Merging #3184 (25ccdfd) into main (a040aa2) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #3184      +/-   ##
==========================================
- Coverage   29.60%   29.59%   -0.01%     
==========================================
  Files         332      332              
  Lines       38902    38910       +8     
==========================================
  Hits        11516    11516              
- Misses      27386    27394       +8     

Impacted Files	Coverage Δ
src/ApiService/ApiService/OneFuzzTypes/Enums.cs	32.39% <ø> (ø)
...ApiService/ApiService/onefuzzlib/NodeOperations.cs	19.29% <0.00%> (-0.35%)	⬇️
...ApiService/ApiService/onefuzzlib/VmssOperations.cs	0.00% <0.00%> (ø)