Move default execution name generation to flyteadmin

[wayner0628]

Tracking issue

• This PR follows up on PR #5637 and migrates the default name generation functionality from flytectl to flyteadmin

Why are the changes needed?

What changes were proposed in this pull request?

• Remove default name generation in flytectl

How was this patch tested?

Setup process

Screenshots

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

#5637

Docs link

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 36.17%. Comparing base (7a91799) to head (6930acc).
Report is 153 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5714   +/-   ##
=======================================
  Coverage   36.17%   36.17%           
=======================================
  Files        1303     1303           
  Lines      109663   109661    -2     
=======================================
+ Hits        39667    39668    +1     
+ Misses      65851    65848    -3     
  Partials     4145     4145           

Flag	Coverage Δ
unittests-datacatalog	51.37% <ø> (ø)
unittests-flyteadmin	55.28% <ø> (ø)
unittests-flytecopilot	12.17% <ø> (ø)
unittests-flytectl	62.21% <ø> (+0.03%)	⬆️
unittests-flyteidl	7.12% <ø> (ø)
unittests-flyteplugins	53.34% <ø> (ø)
unittests-flytepropeller	41.76% <ø> (ø)
unittests-flytestdlib	55.35% <ø> (ø)

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