Fix R-CMD-CHECK errors

[alice-hannah]

See failed run: https://github.com/ScotGovAnalysis/objr/actions/runs/16267543228/job/45926610003?pr=42

Tests causing issues have been commented out until this has been fixed (see commit 2d8cf53).

Issues (both in test-objr.R):

• Line 57: Error in as.character(x): cannot coerce type 'weakref' to vector of type 'character'

• Line 121: Error in httr2::response(status_code = 403, body = list(description = "x")): body must be a raw vector, a path, or a <StreamingBody>, not a list.