FIO-7395: Fixed the issue with loading nested form

[roma-formio]

Link to Jira Ticket

https://formio.atlassian.net/browse/FIO-7395

Description

Fixed the issue using embedded form URL with nested form when using subdirectories path

How has this PR been tested?

Unit tests

Checklist:

• 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