t3c parentdotconfig: ensure ocgmap is ordered by prim, sec

[traeak]

A bug in t3c was found when a topology for a MID is simulated for a non topology MSO delivery service with 2 origins in the primary and secondary groups and round_robin=false. The primary and secondary origin parent cache groups assignments weren't properly being transferred over to the created topology resulting in inconsistent origin ordering in parent.config

This bug fixes that by explicitly assigning primary and secondary parent cache groups to the intermediate struct.

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Which Traffic Control components are affected by this PR?

• Traffic Control Cache Config (t3c, formerly ORT)

What is the best way to verify this PR?

Tested by creating a DS with:

• Not consistent hash (round_robin=false)
• Mid cache group with primary and secondary parent
• Origin assigned from one of each of the above cache groups.

Run t3c multiple times and ensure the parent.config is consistently created.

If this is a bugfix, which Traffic Control versions contained the bug?

• 7.1.0

PR submission checklist

• This PR has tests
• This PR has documentation -- bug fix
• This PR has a CHANGELOG.md entry
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

[codecov]

Codecov Report

Merging #7411 (20e1cae) into master (f7765ff) will increase coverage by 0.01%.
The diff coverage is 85.00%.

@@             Coverage Diff              @@
##             master    #7411      +/-   ##
============================================
+ Coverage     27.03%   27.04%   +0.01%     
  Complexity       98       98              
============================================
  Files           685      685              
  Lines         77279    77301      +22     
  Branches         90       90              
============================================
+ Hits          20892    20909      +17     
- Misses        54399    54404       +5     
  Partials       1988     1988              

Flag	Coverage Δ
golib_unit	48.40% <85.00%> (+0.05%)	⬆️
grove_unit	4.60% <ø> (ø)
t3c_unit	5.32% <ø> (ø)
traffic_monitor_unit	20.43% <ø> (ø)
traffic_ops_unit	22.19% <ø> (ø)
traffic_stats_unit	10.14% <ø> (ø)
unit_tests	23.60% <85.00%> (+0.01%)	⬆️

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

Impacted Files	Coverage Δ
lib/go-atscfg/parentdotconfig.go	65.22% <85.00%> (+0.29%)	⬆️

... and 1 file with indirect coverage changes

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[jpappa200]

Works as expected. consistent ordering of primary and secondary origins. t3c integration tests failed, but they may just need to be started again. +1 once checks are successful and conflicts are resolved.