'Client settings' do not allow using IPv6 CIDR

[DandelionSprout]

Prerequisites

Please answer the following questions for yourself before submitting an issue. YOU MAY DELETE THE PREREQUISITES SECTION.

• I am running the latest version (v0.101.0)
• I checked the documentation and found no answer
• I checked to make sure that this issue has not already been filed

Issue Details

The text box at Client settings → Add client → Identifier, refuse to acknowledge IPv6 CIDR addresses and throws up an error message, as seen in the screenshot below. This applies to all regular and irregular IPv6 CIDR formats that I'm aware of at the time of writing, including:

• 1234:1234:1234:1234:0:0:0:0/64

• 1234:1234:1234:1234:0000:0000:0000:0000/64

• 1234:1234:1234:1234::/64

• [1234:1234:1234:1234:0:0:0:0]/64

• [1234:1234:1234:1234:0:0:0:0/64]

• 2001:610::/29 (Which is an actively used entry that 'Disallowed clients' has no problems with, but which 'Client settings' don't allow.)

• Version of AdGuard Home server:

  • v0.101.0

• How did you setup DNS configuration:

  • N/A

• If it's a router or IoT, please write device model:

  • Raspberry Pi 4

• Operating system and version:

  • N/A

Expected Behavior

IPv6 CIDRs are saveable as a client identifier, the same way IPv4 CIDRs and singular IPv6 IPs always have been.

Actual Behavior

An error note saying "Invalid client ID format" shows up under the textbox, and the Save button doesn't work.

Screenshots

Screenshot:

Additional Information

None that feels important for me to explain at the time of writing.