Return proper responses for SCIM provisioned identities

[tenyo]

This PR adds return responses to ListSCIMProvisionedIdentities and GetSCIMProvisioningInfoForUser, as before it was not possible to get the output of those calls.
Fixes#2338

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[codecov]

Codecov Report

Merging #2474 (ce48d9d) into master (8a4bdb5) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@ Coverage Diff @@## master #2474 +/- ##
=======================================
Coverage 98.03% 98.03% =======================================
Files 122 122 Lines 10695 10705 +10 =======================================
+ Hits 10485 10495 +10 
Misses 144 144 Partials 66 66 

Impacted Files	Coverage Δ
github/scim.go	100.00% <100.00%> (ø)

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[gmlewis]

Thank you, @tenyo !
Just a couple minor nits, please, and then we should be ready for a second LGTM+Approval from any other contributor to this repo.

[gmlewis]

Thank you, @tenyo !
LGTM.

Awaiting second LGTM+Approval from any other contributor to this repo before merging.

[gmlewis]

Thank you, @wesleimp !
Merging.