fix: properly use global cache + mixed routes fix

[xrsv]

Couple changes to have a consistent caching experience + to properly handle mixed protocol

• Only enter cache when all enabled protocols are requested
  • also account for UniversalRouterVersion.V1_2 vs UniversalRouterVersion.V2_0 where different protocols are in play
• when mixed is part of the protocols, then find mixed routes from the provided protocols. E.g. v2,v4,mixed will result in v2+v4+mixed(v2,v4) search. Also protocols=mixed is now not valid/permitted (will 404 in routing api)

Tests

• added unit tests
• tested on personal endpoint
• run routing api e2e tests against personal endpoint

[graphite-app]

Graphite Automations

"Request reviewers once CI passes on smart-order-router repo" took an action on this PR • (02/05/25)

2 reviewers were added and 1 assignee was added to this PR based on Siyu Jiang (See-You John)'s automation.

[jsy1218]

lgtm. my only suggestion is that we monitor the mixed related metrics counts after rollout, to see if it changes. it shouldn't, since swappers should usually request all protocol versions.