fix: Enable Tasks to read "no entry" emoji from Emoji Shortcodes plugin

[claremacrae]

Description

Enable Tasks to read dependsOn emoji - ⛔ - that do not have the Variant Selector 16 (VS16) character.

That invisible character was accidentally included in the Tasks plugin source code, meaning Tasks would only parse dependsOn values with that character.

Note: This does not yet stop Tasks writing out VS16 for this emoji - I will do that as a separate PR as it's quite a large change.

Motivation and Context

Fix #2693.

How has this been tested?

• Adding new tests, which initially failed
• Exploratory testing to confirm that I could reproduce the bug before the fix, and that it was fixed afterwars

Screenshots (if appropriate)

Types of changes

Changes visible to users:

• Bug fix (prefix: fix - non-breaking change which fixes an issue)

Internal changes:

• Tests (prefix: test - additions and improvements to unit tests and the smoke tests)

Checklist

• My code follows the code style of this project and passes yarn run lint.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• My change has adequate Unit Test coverage.

Terms

• My contribution follow this project's contributing guide
• I agree to follow this project's Code of Conduct