Load the package before testing it

[llrs-roche]

The dependency checks on r-universe fail because they run R CMD check, which fails the tests.
The problem seems to come from not loading rtables.officer and using rtables instead of rtables.officer on testthat machinery (not sure of how this affects the results).

I also added the Config/testthat/edition: 3 because it is currently standard and used in other packages and used on rtables.

Note: This code pass checks but doesn't use testthat conditionally even though it is a suggested package.

[github-actions]

✅ All contributors have signed the CLA
_{Posted by the CLA Assistant Lite bot.}

[llrs-roche]

I have read the CLA Document and I hereby sign the CLA

[github-actions]

Code Coverage Summary

Filename              Stmts    Miss  Cover    Missing
------------------  -------  ------  -------  ---------------------------------------------------------------------
R/as_flextable.R        453      24  94.70%   117, 160, 178, 201-205, 323, 569-572, 581, 635, 641, 669-672, 865-869
R/export_as_docx.R      107      28  73.83%   61, 73-100, 222
TOTAL                   560      52  90.71%

Results for commit: 8927874

Minimum allowed coverage is 80%

♻️ This comment has been updated with latest results

[github-actions]

Unit Tests Summary

 1 files   2 suites   9s ⏱️
 7 tests  7 ✅ 0 💤 0 ❌
19 runs  19 ✅ 0 💤 0 ❌

Results for commit 8927874.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Performance Difference

Test Suite	$Status$	Time on main	$±Time$	$±Tests$	$±Skipped$	$±Failures$	$±Errors$
as_flextable	💚	$9.29$	$-2.21$	$0$	$0$	$0$	$0$

Results for commit f8d2411

♻️ This comment has been updated with latest results.

[shajoezhu]

awesome! looks great! thanks @llrs-roche