Fix tests for authenticated calls

[jmaspons]

Don't add httr2::req_oauth_auth_code on R-CMD-check

Avoid errors when testing calls using httptest2. The mock responses have to be generated manually on an authenticated session

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: +8.64 :tada:

Comparison is base (5c8cea1) 57.44% compared to head (42ac005) 66.08%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #5 +/- ## ========================================== + Coverage 57.44% 66.08% +8.64% ========================================== Files 12 12 Lines 625 625 ========================================== + Hits 359 413 +54 + Misses 266 212 -54 ``` | [Impacted Files](https://app.codecov.io/gh/jmaspons/osmapiR/pull/5?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joan+Maspons) | Coverage Δ | | |---|---|---| | [R/osmapi\_request.R](https://app.codecov.io/gh/jmaspons/osmapiR/pull/5?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joan+Maspons#diff-Ui9vc21hcGlfcmVxdWVzdC5S) | `85.71% <100.00%> (ø)` | | ... and [4 files with indirect coverage changes](https://app.codecov.io/gh/jmaspons/osmapiR/pull/5/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joan+Maspons)

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