Tweak UI handle-errors text message a bit

[spacegaier]

Breaking change

Proposed change

Those 4 double quotes always irked me, as well as the apostrophe followed by a double quote.

I changed three things:

1. The expected type and the actual value are now put into round brackets. Makes it easier to read.
2. If no value is provided, then the text now says so.
3. Small wording changes for clarity and readability.

A few examples how it looks now:

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

Example configuration

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

[spacegaier]

Will be covered by PR #8217 (includes proper translations).