chore(rust/signed-doc): Campaign Parameters, Brand Parameters Form Template tests improvements

[Mr-Leshiy]

Description

Updated Campaign Parameters, Brand Parameters Form Template tests by using build_verify_and_publish and create_key_pair_and_publish helper functions

Related Issue(s)

Part of #828

Please confirm the following checks

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream module

[github-actions]

📚 Docs Preview

The docs for this PR can be previewed at the following URL:

https://docs.dev.projectcatalyst.io/libs/chore/brand-param-form-template

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 728/728}$ | ${\color{red}Fail: 0/728}$ |