Add examples to function documentation

[alice-hannah]

Unsure of how best to go about this when considering potential future CRAN release.

See Dependencies and conditional execution section of R packages book.

TLDR:

• Avoid blanket use of \dontrun
• Instead use @examplesIf some_condition()

I think these are the conditions but not sure how to implement them:

• Need internet connection
• Need Objective Connect account/authentication
• Need to obscure any real UUIDs

See also httr2 documentation on package keys.