Link to Jira Ticket

https://formio.atlassian.net/browse/FIO-8477

Description

This PR addresses issues encountered with the formatDate function, originally implemented in the formio.js library, which utilizes the moment-timezone library for timezone formatting. Specifically, the z format option in moment-timezone, used for abbreviated timezone names, does not directly translate to the dayjs library we currently employ. To bridge this functionality gap, the advancedFormat plugin from dayjs is necessary. However, a known issue with dayjs (#1154) results in the generation of GMT+.. formats instead of abbreviated timezone names. Notably, the zzz format option in dayjs correctly provides the full timezone name.

During the process of integrating the advancedFormat plugin and updating the formatDate function, I also discovered and addressed a separate issue related to UTC formatting. Previously, the formatDate function incorrectly used the current date for UTC conversions instead of the provided date value.

How has this PR been tested?

Unit testing

Checklist:

• I have completed the above PR template
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (if applicable)
• My changes generate no new warnings
• My changes include tests that prove my fix is effective (or that my feature works as intended)
• New and existing unit/integration tests pass locally with my changes
• Any dependent changes have corresponding PRs that are listed above