Fix UnicodeEncodeError for emoji-containing URLs

[moritzb57]

Resolved an issue where URLs containing emojis or other non-ASCII characters caused a UnicodeEncodeError when used with urlopen. The fix includes:

• Importing the datetime module to eliminate NameErrors.
• Properly encoding the URL using urllib.parse.quote to ensure all characters are ASCII-safe, which specifically addresses the failure when emojis are included in the URL.
• Maintaining existing error handling while improving clarity and specificity.

This update ensures the ics_calendar integration can handle URLs with special characters without encountering encoding issues.

[franc6]

Thank you!

Sorry it's taken so long for me to get to this.

[franc6]

Just FYI, I should have paid more attention, hanow() was correct; using datetime.now() doesn't use HA's idea of what "now" is, and mocking out datetime.now() isn't really feasible. hanow() can be easily mocked, so the unit tests can work with specific dates and times. I've pushed a fix already. :)