Don't update if already an executable (backport #18221)

[mergify]

This is an automatic backport of pull request #18221 done by Mergify.
Cherry-pick of 2fbedd8 has failed:

On branch mergify/bp/v1.6/pr-18221
Your branch is up to date with 'origin/v1.6'.

You are currently cherry-picking commit 2fbedd834.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   programs/bpf/c/src/invoke/invoke.c
	modified:   programs/bpf/rust/invoke/src/lib.rs
	modified:   programs/bpf/tests/programs.rs

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   runtime/src/message_processor.rs

To fix up this pull request, you can check it out locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

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[codecov]

Codecov Report

Merging #18252 (4979122) into v1.6 (9413051) will decrease coverage by 0.3%.
The diff coverage is 81.5%.

@@            Coverage Diff            @@
##             v1.6   #18252     +/-   ##
=========================================
- Coverage    82.9%    82.5%   -0.4%     
=========================================
  Files         414      424     +10     
  Lines      114017   117361   +3344     
=========================================
+ Hits        94544    96925   +2381     
- Misses      19473    20436    +963