Token healthcheck doesn't seem to check anything

[ashishpandey]

Looking at the token healthcheck implementation here:

aad-auth-proxy/src/handler/handler.go

Line 160 in 42be1cd

if handler.tokenProvider == nil {

Seems this is always a no-op, because tokenProvider always exists and the code block under if will never execute

[ashishpandey]

I have submitted a PR, assuming there is acceptance on the issue and fix