parseCommandLine: Add unit test for multi-line input, remove incorrect help text

[mturley]

Followup to #3592 and #3633.
Resolves https://issues.redhat.com/browse/RHOAIENG-16900.

Description

Adds one more test based on comments on #3633, and removes the now-incorrect help text directing users to only have one argument per line now that we support single-line arg lists.

Help text before:

Help text after:

How Has This Been Tested?

No manual testing, this is just a unit test and a microcopy change.

Test Impact

See new unit test - just making sure the util still handles multi-line args properly.

Request review criteria:

Self checklist (all need to be checked):

• The developer has manually tested the changes and verified that the changes work
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has added tests or explained why testing cannot be added (unit or cypress tests for related changes)

If you have UI changes:

• Included any necessary screenshots or gifs if it was a UI change.
• Included tags to the UX team if it was a UI/UX change.

After the PR is posted & before it merges:

• The developer has tested their solution on a cluster by using the image produced by the PR to main

[mturley]

/hold
Needs to wait for #3633 to merge.

[mturley]

cc @vconzola @yih-wang

[mturley]

/retest

[YuliaKrimerman]

/lgtm

[vconzola]

lgtm

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.44%. Comparing base (f03527b) to head (c038ede).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3634      +/-   ##
==========================================
+ Coverage   85.41%   85.44%   +0.03%     
==========================================
  Files        1406     1406              
  Lines       32325    32325              
  Branches     9069     9069              
==========================================
+ Hits        27609    27619      +10     
+ Misses       4716     4706      -10     

Files with missing lines	Coverage Δ
...projects/kServeModal/ServingRuntimeArgsSection.tsx	94.11% <ø> (ø)

... and 5 files with indirect coverage changes

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[mturley]

/unhold

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

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[manaswinidas]

/lgtm