FIO-7406 Fixed plain Textarea interpolating data in readonly mode

[antonSoftensity]

Link to Jira Ticket

https://formio.atlassian.net/browse/FIO-7406

Description

Previously, all types of Textarea inputs were interpolated by default in readonly mode (i.e. submission view). This change disables interpolating when custom editors are not used.

How has this PR been tested?

Tested locally

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

[travist]

👍