FIO-8677: Fixes an issue where its possible to draweon Signature on the View tab of PDF form

[alexandraRamanenka]

Link to Jira Ticket

https://formio.atlassian.net/browse/FIO-8677

Description

showCanvas(true) should be never called if component is disabled since it will make it drawable (which should not happen in disabled state)

Breaking Changes / Backwards Compatibility

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Dependencies

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How has this PR been tested?

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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