Make key_c_hint strings consistent

[NoRi2909]

At the bottom of setting the ui::tips::key_c_hint shows up in rotation with other hints:

When you do so the Quick search dialog opens and displays this hint at the bottom:

The latter should be made consistent with the first by using "command dialog" in both places as "c" maps to "command".

Proposed change

Makes the 'key_c_hint' identical by using:
"Press 'c' on any page to open the command dialog"

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue or discussion:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io