[Cosmos] Extract a StoreResult test factory to replace the 20-arg positional constructor in unit tests

[mbhaskar]

Summary

Follow-up from PR #48914 (review feedback from @kushagraThapar).

The 20-arg positional new StoreResult(...) constructor is repeated across many test methods (in ConsistencyWriterTest.java at lines ~667, 725, 757, 779, 834, 894, 903, 919, 947, and several more in QuorumReaderTest.java). Each invocation follows the same pattern: most arguments are constants/null/false, with only 2–3 meaningful per test (replica role, isThrottledException, isValid).

This positional-constructor accretion has been growing across multiple PRs and makes tests verbose and fragile.

Proposed change

Extract a StoreResultTestFactory (or builder) with named, intent-revealing methods, e.g.:

• throttled429()
• valid(int globalCommittedLsn)
• unhealthy(replicaRole)

Benefits:

• New tests become 1-line setup instead of ~20-line setup.
• When the StoreResult constructor changes (e.g. adding a 21st arg), only the factory updates instead of N test sites.
• Test intent becomes self-documenting (throttled429() reads as a behavior, not a 20-arg ctor invocation).

Scope

Test-only refactor; no production behavior change. Update existing StoreResult-based tests in:

• sdk/cosmos/azure-cosmos-tests/.../directconnectivity/ConsistencyWriterTest.java
• sdk/cosmos/azure-cosmos-tests/.../directconnectivity/QuorumReaderTest.java

Context

Reviewer noted this is "not a blocker for [PR #48914] but worth scheduling as a follow-up before the next test wave lands on top."