Retain the previous OMR prefix based address for longer time to avoid routing issues

[sarveshkumarv3]

Currently whenever the OMR prefix changes there are packet drops encountered for any ongoing transmission.

The thread networking interface (wpan) removes the old OMR prefix even before all the accessories could register to the SRP server with the new OMR prefix based address. This causes application to still resolve old address but not able to route it forward.

Similar to context ID which is retained for upto 5mins for SED to wake up and retrieve the network data, can the old OMR prefix based address be assigned to the wpan interface on the border router for 5mins, so that any ongoing transmissions (till the accessory regiters to the SRP server) is not disrupted due to routing issues at the border router?

[abtink]

@sarveshkumarv3, this is already supported and implemented for all SLAAC addresses (which include OMR-based addresses).

• Check out this PR: [slaac] implement address deprecation mechanism #9585
• The deprecation interval is 300 seconds (5 minutes).

Other related PRs to this (regarding BR function):

• [routing-manager] deprecate OMR/on-mesh prefixes when removed from netdata #9599

Also check SPEC-1222 and #9636