feat: Add hashSha256 method for SHA-256 hashing

[jaissica12]

Background

• Added hashSha256 method and related helpers to provide SHA-256 hashing functionality for advertisers using the mParticle Web SDK without requiring the Rokt Kit dependency.
• Code reference: attribute-service , hash-string, rokt-docs

What Has Changed

• Added hashSha256 method
• Added unit tests for hashing. Referred the same test cases from sdk-webto compare the hashed values

Screenshots/Video

• {Include any screenshots or video demonstrating the new feature or fix, if applicable}

Checklist

• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have added tests that prove my fix is effective or that my feature works.
• I have tested this locally.

Additional Notes

• {Any additional information or context relevant to this PR}

Reference Issue (For employees only. Ignore if you are an outside contributor)

• Closes https://go/j/SDKE-452

[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

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

See analysis details on SonarQube Cloud