Extend proactive token refresh to client_credentials

[Robbie-Microsoft]

MSAL is expected to refresh the token when the refresh_in value expires. This is already implemented for AcquireTokenSilent but is not implemented for client_credentials. This PR implements refresh_in for client_credentials.

I've implemented the long term solution from the refresh spec.

[codecov-commenter]

Codecov Report

Merging #6102 (21ae216) into dev (81d34b4) will decrease coverage by 1.84%.
Report is 267 commits behind head on dev.
The diff coverage is 67.63%.

Flag	Coverage Δ
msal-angular	96.73% <92.78%> (+0.22%)	⬆️
msal-browser	85.53% <ø> (-0.94%)	⬇️
msal-common	83.07% <ø> (-1.48%)	⬇️
msal-core	?
msal-node	79.86% <ø> (-3.53%)	⬇️
msal-node-extensions	68.67% <61.03%> (-6.97%)	⬇️
msal-react	94.24% <ø> (-0.45%)	⬇️
node-token-validation	?

Files Changed	Coverage Δ
...ions/msal-node-extensions/src/utils/Environment.ts	20.51% <0.00%> (-22.08%)	⬇️
lib/msal-angular/src/msal.interceptor.ts	100.00% <ø> (ø)
lib/msal-angular/src/msal.module.ts	100.00% <ø> (ø)
lib/msal-angular/src/msal.navigation.client.ts	93.33% <ø> (+0.47%)	⬆️
lib/msal-angular/src/msal.redirect.component.ts	100.00% <ø> (ø)
lib/msal-angular/src/msal.service.ts	100.00% <ø> (ø)
lib/msal-angular/src/packageMetadata.ts	100.00% <ø> (ø)
...b/msal-browser/src/app/IPublicClientApplication.ts	42.42% <ø> (-1.33%)	⬇️
...ib/msal-browser/src/app/PublicClientApplication.ts	67.44% <ø> (-27.89%)	⬇️
...er/src/broker/nativeBroker/NativeMessageHandler.ts	86.29% <ø> (+0.33%)	⬆️
... and 73 more

... and 160 files with indirect coverage changes

[bgavrilMS]

Not implemented as availability feature.

[bgavrilMS]

RefreshOn is optional, not mandatory.