multiregionccl: unskip TestColdStartLatency

While merging https://github.com/cockroachdb/cockroach/pull/150105, we found that TestColdStartLatency began failing.

https://github.com/cockroachdb/cockroach/actions/runs/16285620967?pr=150105
```
=== RUN TestColdStartLatency
test_log_scope.go:165: test logs captured to: outputs.zip/logTestColdStartLatency2575762032
test_log_scope.go:76: use -show-logs to present logs inline
cold_start_latency_test.go:184: 0 alter range meta configure zone using constraints = '{"+region=us-east1": 1, "+region=us-west1": 1, "+region=europe-west1": 1}';
cold_start_latency_test.go:184: 0
BEGIN;
SET LOCAL autocommit_before_ddl = false;
ALTER DATABASE system PRIMARY REGION "us-east1";
ALTER DATABASE system ADD REGION "us-west1";
ALTER DATABASE system ADD REGION "europe-west1";
COMMIT;
cold_start_latency_test.go:358: pre running test to allocate instance IDs
cold_start_latency_test.go:339: done 8 region=us-west1,az=c 2.477531466s
cold_start_latency_test.go:339: done 2 region=europe-west1,az=c 4.138645721s
cold_start_latency_test.go:339: done 0 region=europe-west1,az=a 3.347701747s
cold_start_latency_test.go:339: done 1 region=europe-west1,az=b 2.753756097s
cold_start_latency_test.go:339: done 6 region=us-west1,az=a 1.314962776s
cold_start_latency_test.go:339: done 3 region=us-east1,az=a 1.987200188s
cold_start_latency_test.go:339: done 4 region=us-east1,az=b 5.023784982s
cold_start_latency_test.go:339: done 5 region=us-east1,az=c 1.878972213s
cold_start_latency_test.go:339: done 7 region=us-west1,az=b 1.256219041s
cold_start_latency_test.go:359: result [region=europe-west1,az=a region=europe-west1,az=b region=europe-west1,az=c region=us-east1,az=a region=us-east1,az=b region=us-east1,az=c region=us-west1,az=a region=us-west1,az=b region=us-west1,az=c] [3.347701747s 2.753756097s 4.138645721s 1.987200188s 5.023784982s 1.878972213s 1.314962776s 1.256219041s 2.477531466s]
cold_start_latency_test.go:360: running test with no connectivity from sql pods to remote regions
cold_start_latency_test.go:339: done 8 region=us-west1,az=c 1.314442426s
cold_start_latency_test.go:339: done 0 region=europe-west1,az=a 3.25512969s
cold_start_latency_test.go:339: done 1 region=europe-west1,az=b 3.296278306s
cold_start_latency_test.go:339: done 2 region=europe-west1,az=c 2.887563057s
cold_start_latency_test.go:339: done 3 region=us-east1,az=a 2.004228176s
cold_start_latency_test.go:339: done 4 region=us-east1,az=b 5.034713443s
cold_start_latency_test.go:339: done 5 region=us-east1,az=c 5.086950821s
cold_start_latency_test.go:333:
Error Trace: pkg/ccl/multiregionccl/cold_start_latency_test.go:333
src/runtime/asm_amd64.s:1700
Error: Received unexpected error:
failed to connect to `user=foo database=defaultdb`: 127.0.0.1:44873 (127.0.0.1): server error: ERROR: internal error while retrieving user account memberships: operation "get-user-session" timed out after 10.001s (given timeout 10s): internal error while retrieving user account: get auth info error: interrupted during singleflight load-value:authinfo-foo-3-3: context deadline exceeded (SQLSTATE 28000)
Test: TestColdStartLatency
```

We may need to change the timeout settings or figure out a way to make the test quicker.

Jira issue: CRDB-52620

Epic CRDB-45396