Pad short uuid with 0's

[Jc2k]

In CoAP we are seeing squished UUID's like 45E5011ECB4000A80FF2603DE. These need padding to 32 chars with leading 0 before normalising.

E.g. 45E5011ECB4000A80FF2603DE should become 00000004-5E50-11EC-B400-0A80FF2603DE.

Via https://community.home-assistant.io/t/homekit-accessory-protocol-hap-over-coap-udp-was-nanoleaf-essentials-bulb-via-thread-coap/335167/346?u=jc2k

[codecov]

Codecov Report

Base: 66.70% // Head: 66.70% // No change to project coverage 👍

Coverage data is based on head (a1fa41c) compared to base (c878746).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #274   +/-   ##
=======================================
  Coverage   66.70%   66.70%           
=======================================
  Files          71       71           
  Lines        6701     6701           
=======================================
  Hits         4470     4470           
  Misses       2231     2231           

Flag	Coverage Δ
unittests	66.70% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
aiohomekit/uuid.py	100.00% <100.00%> (ø)

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[Jc2k]

@bdraco fairly small fix for a thread device I want to get into next beta tag, but shared function with ip and ble so thought I better give you a heads up.