Fix agent tunnel address with dedicated supervisor port

[brandond]

Proposed Changes

Fix issue where rke2 tunnel was trying to connect to apiserver port instead of supervisor:

Note the incorrect port for the tunnel connection in RKE2 where the apiserver and supervisor are on different ports:

time="2024-12-06T20:35:57Z" level=info msg="Started tunnel to 172.17.0.2:6443"
time="2024-12-06T20:35:57Z" level=info msg="Stopped tunnel to 127.0.0.1:9345"
time="2024-12-06T20:35:57Z" level=info msg="Connecting to proxy" url="wss://172.17.0.2:6443/v1-rke2/connect"
time="2024-12-06T20:35:57Z" level=info msg="Proxy done" err="context canceled" url="wss://127.0.0.1:9345/v1-rke2/connect"
time="2024-12-06T20:35:57Z" level=info msg="error in remotedialer server [400]: websocket: close 1006 (abnormal closure): unexpected EOF"
time="2024-12-06T20:35:57Z" level=error msg="Failed to connect to proxy. Response status: 403 - 403 Forbidden. Response body: {\"kind\":\"Status\",\"apiVersion\":\"v1\",\"metadata\":{},\"status\":\"Failure\",\"message\":\"forbidden: User \\\"system:node:e8266a6ea5f6\\\" cannot get path \\\"/v1-rke2/connect\\\"\",\"reason\":\"Forbidden\",\"details\":{},\"code\":403}\n" error="websocket: bad handshake"
time="2024-12-06T20:35:57Z" level=error msg="Remotedialer proxy error; reconnecting..." error="websocket: bad handshake" url="wss://172.17.0.2:6443/v1-rke2/connect"

Types of Changes

bugfix

Verification

requires pull-through to rke2

Testing

Linked Issues

• Embedded load-balancer behavior is flakey and hard to understand #11334

User-Facing Change

Further Comments

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.19%. Comparing base (e9cf3a7) to head (0cbfe94).
Report is 4 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #11427      +/-   ##
==========================================
- Coverage   47.66%   43.19%   -4.48%     
==========================================
  Files         181      181              
  Lines       18797    18794       -3     
==========================================
- Hits         8960     8118     -842     
- Misses       8490     9477     +987     
+ Partials     1347     1199     -148     

Flag	Coverage Δ
e2etests	35.48% <100.00%> (-7.34%)	⬇️
inttests	18.73% <0.00%> (-16.09%)	⬇️
unittests	14.26% <0.00%> (+<0.01%)	⬆️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[brandond]

OK, all done poking at this one.