fix: remove MountReturn from scaffolded ct support file

[ZachJW34]

User facing changelog

Remove unused MountReturn import from scaffolded support file

Additional details

MountReturn isn't an exported or defined type for @cypress/vue so it was throwing an error on project setup. We never used it anyway since we were scaffolding:

declare global {
  namespace Cypress {
    interface Chainable {
      mount: typeof mount
    }
  }
}

Since we do typeof mount, the return type is derived from mount.

How has the user experience changed?

The component.ts file no longer has an invalid import.

PR Tasks

• Have tests been added/updated?
• Has the original issue (or this PR, if no issue exists) been tagged with a release in ZenHub? (user-facing changes only)
• Has a PR for user-facing changes been opened in cypress-documentation?
• Have API changes been updated in the type definitions?
• Have new configuration options been added to the cypress.schema.json?

[cypress-bot]

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[cypress]

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Test summary

17872 • 0 • 217 • 0 • 0

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Run details

Project	cypress
Status	Passed
Commit	e72068e
Started	Apr 18, 2022 6:17 PM
Ended	Apr 18, 2022 6:31 PM
Duration	13:51 💡
OS	Linux Debian - 10.10
Browser	Multiple

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