Speaking error if the extension is not unlocked

[faboweb]

Describe the bug
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When the extension is locked, some commands just fail or show weird errors.

To Reproduce
Steps to reproduce the behavior:

• have a locked extension (by i.e. reloading it in brave://extensions/)
• execute a signing command

Expected behavior
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The commands should open the extension and prompt the user to unlock it.

Screenshots
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Additional context
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[faboweb]

A bit more complicated. Could hook into the background entry point where enable is also handled.