fix: Add uniqueId to key in bypasscache_test.dart to have unique key …

[sitaram-kalluri]

- What I did

• Fix the intermittent failure of the by_pass_cache key test.

- How I did it

• Added a unique Id to the key and the value to ensure a new key is generated for each test. Without the unique key, the same key is being used for each test run and the previous test value is being synced to the client causing intermittent failures
• Added SyncOptions to ensure assertion waits until the key is synced to the client/server
• Added TTL of 15 minutes, so that the key will be deleted subsequently
• Removed the version method that returns the server version which is no longer needed. Checks if the server version is greater than 3.0.29. All test-atSign's are moved to 3.0.31.

- How to verify it

• The E2E test should pass