Alignment for Conditions messages format

[tataruty]

Proposed changes

Problem:
We have some inconsistent messages in status conditions of resources.

(below, we use ConditionType/Status/Reason notation)

A few examples:
"The route is accepted" for HTTPRoute Accepted/True/Accepted . However, we have "GatewayClass is accepted" for GatewayClass Accepted/True/Accepted.
"unsupported value" for Listener Accepted/False/UnsupportedValue. Note that in most other messages, first letter is capitalized.
"invalid backendTLSPolicy" for BackendTLSPolicy Accepted/False/Invalid. Note: first letter is not capitalized, backendTLSPolicy is spelled differently from other similar places. Needed "BackendTLSPolicy"
Acceptance criteria:

Come up with consistent style
Capture rules if necessary
Bring messages with accordance to the style

Solution:
Decided to use next format:

1. Start with The if can be
2. Second word make capitalized as it is used everywhere in description for all: Listener, Gateway, GatewayClass, InferencePool and even Route
3. Replace split to combined, if there is both used, like inference pool => InferencePool.
4. Example: "The Gateway is invalid"

Testing: Unit tests.

Please focus on (optional):
There is one case when Condition message is built as an error and since error cannot be capitalized, added linter exception for that line

Closes #1809

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

Release notes

If this PR introduces a change that affects users and needs to be mentioned in the release notes,
please add a brief note that summarizes the change.

NONE

[codecov]

Codecov Report

❌ Patch coverage is 53.84615% with 30 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.09%. Comparing base (ec97d7a) to head (b2bb2fc).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/controller/state/conditions/conditions.go	6.25%	30 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4253      +/-   ##
==========================================
- Coverage   86.15%   86.09%   -0.06%     
==========================================
  Files         131      131              
  Lines       14196    14205       +9     
  Branches       35       35              
==========================================
  Hits        12230    12230              
- Misses       1764     1769       +5     
- Partials      202      206       +4     

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