feat: improved client performance when Bypasser is disabled

[petruki]

This pull request updates the package version from 1.2.0 to 1.2.1 and introduces a safeguard to the Bypasser class to ensure key searching only occurs when bypassing is enabled. Below are the most important changes:

Version bump and workflow updates:

• Updated __version__ in switcher_client/version.py, sonar.projectVersion in sonar-project.properties, and the workflow dispatch description in .github/workflows/publish-anaconda.yml to reflect version 1.2.1. [1] [2] [3]

Bypasser class enhancements:

• Added a _bypass_enabled flag to the Bypasser class and set it to True when assume is called to explicitly control when bypassing is active.
• Updated the search_key method to return None if bypassing is not enabled, preventing unintended key lookups when bypassing is disabled.

Performance results
Switcher Client SDK: Mean +- std dev: 377 ns +- 0 ns

Benchmark summary

Metric	Value
SDK	Switcher Client SDK
Time/iteration (avg)	377.30 ns
Iterations/s	2,650,386.73
Min	376.93 ns
Max	378.03 ns
p75	377.55 ns
p99	378.01 ns
p99.5	378.02 ns

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud