Fix status code and alerts when querying delivery service with no SSL keys

[srijeet0406]

This PR fixes #4393.

---

Which Traffic Control components are affected by this PR?

• Traffic Ops

What is the best way to verify this PR?

Follow the steps in the related Github issue #4393.

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

• master

PR submission checklist

• This PR has tests
• This PR has documentation
• 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 #7640 (b8dc675) into master (7d5cebe) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master    #7640      +/-   ##
============================================
- Coverage     30.13%   30.12%   -0.01%     
  Complexity       98       98              
============================================
  Files           794      794              
  Lines         84060    84077      +17     
  Branches        907      907              
============================================
- Hits          25333    25332       -1     
- Misses        56597    56615      +18     
  Partials       2130     2130              

Flag	Coverage Δ
golib_unit	48.29% <ø> (-0.01%)	⬇️
grove_unit	4.60% <ø> (ø)
t3c_unit	5.28% <ø> (ø)
traffic_monitor_unit	21.30% <ø> (ø)
traffic_ops_integration	69.42% <ø> (ø)
traffic_ops_unit	22.95% <0.00%> (-0.01%)	⬇️
traffic_portal_v2	73.78% <ø> (ø)
traffic_stats_unit	10.14% <ø> (ø)
unit_tests	27.25% <0.00%> (-0.01%)	⬇️
v3	57.79% <ø> (ø)
v4	79.18% <ø> (ø)
v5	78.63% <ø> (ø)

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

Impacted Files	Coverage Δ
...fic_ops/traffic_ops_golang/deliveryservice/keys.go	31.86% <0.00%> (-0.97%)	⬇️
..._ops/traffic_ops_golang/deliveryservice/sslkeys.go	0.00% <0.00%> (ø)
..._golang/trafficvault/backends/postgres/postgres.go	0.47% <0.00%> (ø)

... and 1 file with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[ericholguin]

Looks good! Getting 200 for API v4 and 404 for API v5