fix (contracts): update verifier contract to mainnet version v0.9.8

[silathdiir]

Purpose or design rationale of this PR

Update verifier contract to v0.9.8. No need to deploy, just update the code to avoid confusing for who read our code.

PR title

Your PR title must follow conventional commits (as we are doing squash merge for each PR), so it must start with one of the following types:

• build: Changes that affect the build system or external dependencies (example scopes: yarn, eslint, typescript)
• ci: Changes to our CI configuration files and scripts (example scopes: vercel, github, cypress)
• docs: Documentation-only changes
• feat: A new feature
• fix: A bug fix
• perf: A code change that improves performance
• refactor: A code change that doesn't fix a bug, or add a feature, or improves performance
• style: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
• test: Adding missing tests or correcting existing tests

Deployment tag versioning

Has tag in common/version.go been updated or have you added bump-version label to this PR?

• No, this PR doesn't involve a new deployment, git tag, docker image tag
• Yes

Breaking change label

Does this PR have the breaking-change label?

• No, this PR is not a breaking change
• Yes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (ef673c9) 48.90% compared to head (b47d271) 48.92%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1049      +/-   ##
===========================================
+ Coverage    48.90%   48.92%   +0.01%     
===========================================
  Files          158      158              
  Lines        12710    12705       -5     
===========================================
  Hits          6216     6216              
+ Misses        6064     6059       -5     
  Partials       430      430              

Flag	Coverage Δ
contracts	53.50% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.