[PAYSHIP-3580] Express checkout fixes

[L3RAZ]

Self-Checks

• I have performed a self-review of my code.
• I have updated/added necessary technical documentation in the README file.

JIRA task link

Resolves: PAYSHIP-3580

Summary

QA Checklist Labels

• Bug fix?
• New feature?
• Improvement?
• Technical debt?
• Covered by tests?

QA Checklist

Additional Context

Frontend Changes

[!] Don't forget to include JIRA task number in PR name or branch name. [!]

[!] Don't forget to update changelog.md with new changes. [!]

• Verify if the version is correct.
• Update demo environments used for testing.
• Ensure changelog contains all changes.
• Update documentation if needed.
• Test if everything works properly.