Call config.isQuotaEnabled instead of testing the reference

[delthas]

lib/utilities/monitoringHandler.js gated quota metrics on
config.isQuotaEnabled — the function reference, not a call — at two sites,
so both were always true.

The two bugs cancelled out. Because the registration gate was always true all
six quota metrics always existed, so the always-true gate in crrCacheToProm
never touched an unregistered gauge. Fixing only the registration site would
crash it, and would also crash the metric observation in the scuba wrapper,
which the Veeam capacity route reaches with no quota gating at all
(lib/routes/veeam/list.js, lib/routes/veeam/utils.js) — in a finally
block, so the TypeError would replace the original error. Every metric touch
point is therefore guarded to tolerate a metric that was never registered:
three in the scuba wrapper, three in quotaUtils.js.

This changes an operator-visible surface: the six s3_cloudserver_quota_*
metrics are now absent when quota is disabled, where previously they were
always registered. Anything scraping or alerting on them in a non-quota
deployment will see them disappear.

An alternative, recorded on the ticket, is to drop the dead conditional and
register unconditionally — preserving today's behaviour exactly with no
metric-surface change.

Issue: CLDSRV-972

[codecov]

Codecov Report

❌ Patch coverage is 94.44444% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.36%. Comparing base (43f7fee) to head (fcefd5a).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
lib/utilities/monitoringHandler.js	93.75%	2 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
lib/api/apiUtils/quotas/quotaUtils.js	100.00% <100.00%> (ø)
lib/utilization/scuba/wrapper.js	100.00% <100.00%> (ø)
lib/utilities/monitoringHandler.js	88.77% <93.75%> (-2.05%)	⬇️

@@                                      Coverage Diff                                      @@
##           improvement/CLDSRV-971/quota-metrics-retrieval-code-label    #6253      +/-   ##
=============================================================================================
- Coverage                                                      86.38%   86.36%   -0.02%     
=============================================================================================
  Files                                                            212      212              
  Lines                                                          14567    14567              
=============================================================================================
- Hits                                                           12583    12581       -2     
- Misses                                                          1984     1986       +2     

Flag	Coverage Δ
checksums-disabled-tests	35.29% <75.00%> (-0.05%)	⬇️
file-ft-tests	69.98% <77.77%> (-0.03%)	⬇️
file-ft-tests-null-compat	70.41% <77.77%> (-0.11%)	⬇️
kmip-ft-tests	28.04% <38.88%> (-0.07%)	⬇️
mongo-v0-ft-tests	71.08% <77.77%> (-0.02%)	⬇️
mongo-v1-ft-tests	71.01% <77.77%> (-0.08%)	⬇️
multiple-backend	36.04% <75.00%> (-0.05%)	⬇️
s3c-ft-tests-v0	65.01% <75.00%> (-0.05%)	⬇️
s3c-ft-tests-v0-null-compat	65.07% <75.00%> (-0.05%)	⬇️
s3c-ft-tests-v1	64.99% <75.00%> (-0.05%)	⬇️
sur-tests	36.63% <75.00%> (ø)
sur-tests-inflights	39.43% <72.22%> (ø)
unit	73.83% <94.44%> (+<0.01%)	⬆️
utapi-v2-tests	35.27% <75.00%> (-0.05%)	⬇️

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

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[delthas]

Requested @francoisferrand in place of Maha Benzekri, who is currently on PTO.

[bert-e]

Hello delthas,

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[bert-e]

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