[tests] implement DinD test for SRP TC 2.13 Device Address Update

[jwhui]

Implement Thread 1.3 SRP test case 2.13 (Thread Device address update) using the Docker-in-Docker integration testing framework.

This includes:

• Adding expect script tests/scripts/expect/dind_srp_tc_13.exp.
• Registering a service with OMR address, then updating host addresses to include both ML-EID and a new OMR address.
• Using Python's ipaddress library to compute a new OMR address sharing the same prefix but with a custom interface ID (e.g. suffix ::63) and formatting it to match OpenThread's uncompressed hex segment format.
• Verifying unicast DNS resolution of updated host addresses on ED_1.
• Verifying multicast mDNS resolving on AIL (Eth_1 / test-client), confirming that the old OMR address is absent, and the new OMR address is present.
• Verifying multicast mDNS KEY record queries on AIL return RCODE=0.
• Hooking dind_srp_tc_13.exp into tests/scripts/test_dind_dns_sd.sh.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 44.65%. Comparing base (2b41187) to head (a54caea).
⚠️ Report is 1523 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #3415       +/-   ##
===========================================
- Coverage   55.77%   44.65%   -11.12%     
===========================================
  Files          87      143       +56     
  Lines        6890    17274    +10384     
  Branches        0     1417     +1417     
===========================================
+ Hits         3843     7714     +3871     
- Misses       3047     9014     +5967     
- Partials        0      546      +546     

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[jwhui]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces two new integration tests for the DNS-SD/SRP features in Docker-in-Docker environments: dind_srp_tc_11.exp (testing SRP recovery after a border router reboot) and dind_srp_tc_13.exp (testing SRP device address updates). It also adds helper procedures to _common.exp for managing test client containers and configures the main test runner script test_dind_dns_sd.sh to execute these new tests. There are no review comments, and I have no additional feedback to provide.