Regression Fix: ISXB-1674 - Input actions asset not converted correctly when upgrading from 1.14.1

[AswinRajGopal]

Description

Bug: https://jira.unity3d.com/browse/ISXB-1674
Port: 1.14.X

Preserve original tokens and only touch the enum values. That means processor names, order, legacy processors, and formatting survive unchanged so the editor no longer collapses or marks them “Obsolete”.
Avoid whole string rewrites, which previously caused mismatches between what the editor expected and what was written back and only assign a new processor string if something actually changed.

Testing status & QA

Verified manually with the attached repro project.

Overall Product Risks

Complexity: 0
Halo Effect: 0

Comments to reviewers

Please describe any additional information such as what to focus on, or historical info for the reviewers.

Checklist

Before review:

• Changelog entry added.
  • Explains the change in Changed, Fixed, Added sections.
  • For API change contains an example snippet and/or migration example.
  • JIRA ticket linked, example (case %%). If it is a private issue, just add the case ID without a link.
  • Jira port for the next release set as "Resolved".
• Tests added/changed, if applicable.
  • Functional tests Area_CanDoX, Area_CanDoX_EvenIfYIsTheCase, Area_WhenIDoX_AndYHappens_ThisIsTheResult.
  • Performance tests.
  • Integration tests.
• Docs for new/changed API's.
  • Xmldoc cross references are set correctly.
  • Added explanation how the API works.
  • Usage code examples added.
  • The manual is updated, if needed.

During merge:

• Commit message for squash-merge is prefixed with one of the list:
  • NEW: ___.
  • FIX: ___.
  • DOCS: ___.
  • CHANGE: ___.
  • RELEASE: 1.1.0-preview.3.

After merge:

• Create forward/backward port if needed. If you are blocked from creating a forward port now please add a task to ISX-1444.

[codecov-github-com]

Codecov Report

Attention: Patch coverage is 11.20000% with 111 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...nputsystem/InputSystem/Actions/InputActionAsset.cs	11.20%	111 Missing ⚠️

@@             Coverage Diff             @@
##           develop    #2242      +/-   ##
===========================================
+ Coverage    68.14%   76.62%   +8.48%     
===========================================
  Files          367      465      +98     
  Lines        53685    88011   +34326     
===========================================
+ Hits         36584    67442   +30858     
- Misses       17101    20569    +3468     

Flag	Coverage Δ
inputsystem_MacOS_2021.3	5.90% <0.00%> (?)
inputsystem_MacOS_2021.3_project	77.96% <11.20%> (?)
inputsystem_MacOS_2022.3	5.36% <0.00%> (?)
inputsystem_MacOS_2022.3_project	74.51% <11.20%> (?)
inputsystem_MacOS_6000.0	5.18% <0.00%> (?)
inputsystem_MacOS_6000.0_project	76.43% <11.20%> (?)
inputsystem_MacOS_6000.2	5.18% <0.00%> (?)
inputsystem_MacOS_6000.2_project	76.42% <11.20%> (?)
inputsystem_MacOS_6000.3	5.18% <0.00%> (?)
inputsystem_MacOS_6000.3_project	76.42% <11.20%> (?)
inputsystem_MacOS_6000.4	5.18% <0.00%> (?)
inputsystem_MacOS_6000.4_project	76.42% <11.20%> (?)
inputsystem_Ubuntu_2021.3	5.90% <0.00%> (?)
inputsystem_Ubuntu_2021.3_project	77.88% <11.20%> (?)
inputsystem_Ubuntu_2022.3	5.37% <0.00%> (?)
inputsystem_Ubuntu_2022.3_project	74.31% <11.20%> (?)
inputsystem_Ubuntu_6000.0	5.18% <0.00%> (?)
inputsystem_Ubuntu_6000.0_project	76.24% <11.20%> (?)
inputsystem_Ubuntu_6000.2	5.18% <0.00%> (?)
inputsystem_Ubuntu_6000.2_project	76.24% <11.20%> (?)
inputsystem_Ubuntu_6000.3	5.18% <0.00%> (?)
inputsystem_Ubuntu_6000.3_project	76.24% <11.20%> (?)
inputsystem_Ubuntu_6000.4	5.18% <0.00%> (?)
inputsystem_Ubuntu_6000.4_project	76.24% <11.20%> (?)
inputsystem_Windows_2021.3	5.90% <0.00%> (?)
inputsystem_Windows_2021.3_project	78.11% <11.20%> (?)
inputsystem_Windows_2022.3	5.36% <0.00%> (?)
inputsystem_Windows_2022.3_project	74.65% <11.20%> (?)
inputsystem_Windows_6000.0	5.18% <0.00%> (?)
inputsystem_Windows_6000.0_project	76.57% <11.20%> (?)
inputsystem_Windows_6000.2	5.18% <0.00%> (?)
inputsystem_Windows_6000.2_project	76.56% <11.20%> (?)
inputsystem_Windows_6000.3	5.18% <0.00%> (?)
inputsystem_Windows_6000.3_project	76.56% <11.20%> (?)
inputsystem_Windows_6000.4	5.18% <0.00%> (?)
inputsystem_Windows_6000.4_project	76.56% <11.20%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...nputsystem/InputSystem/Actions/InputActionAsset.cs	59.28% <11.20%> (-14.80%)	⬇️

... and 99 files with indirect coverage changes

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