sso: rename request timing metric

[Jusshersmith]

Problem

We send 'request' metrics in various places however they aren't all the same type of metric, which makes things confusing while actually utilising the metrics unless the actual code is inspected.

For example:

We send these 'request' metrics as time values: https://github.com/buzzfeed/sso/blob/f302bca23e5b8b841dfb411d3d43df344772e6a6/internal/auth/metrics.go#L69

We send these 'provider.request' metrics as incremented values: https://github.com/buzzfeed/sso/blob/521ff9c1529f7015d9cdc4d2a75832192535db18/internal/auth/providers/okta.go#L179

Solution

Slightly rename the metrics that are of a time type so we can easily distinguish between the value types.

Note

This could be classed as a 'breaking' change for anyone using this metric for reporting/monitoring purposes, however not for the actual functionality of SSO itself.

• This also now includes some test additions, largely ported over from the sso_auth metric tests.

[codecov[bot]]

Codecov Report

Merging #208 into master will increase coverage by 0.55%. The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #208      +/-   ##
=========================================
+ Coverage   62.14%   62.7%   +0.55%     
=========================================
  Files          53      53              
  Lines        4169    4169              
=========================================
+ Hits         2591    2614      +23     
+ Misses       1391    1367      -24     
- Partials      187     188       +1

Impacted Files	Coverage Δ
internal/auth/metrics.go	94.73% <100%> (ø)	:arrow_up:
internal/proxy/metrics.go	87.87% <100%> (+69.69%)	:arrow_up: