replaced utils::getFromNamespace() with exported rtables.officer fu…

[eanokian]

…nctions

Pull Request

This PR needs prior acceptance of other 2 external PRs:

• 66 export functions insightsengineering/rtables.officer#68
• export insert_empty_rows() and get_file_name() pharmaverse/tidytlg#61
  Once these are approved and released to CRAN, then this PR can be sent for review (i.e. "undraft" it).

Fixes #174
In the docx exporter function, replace the utils::getFromNamespace() with calls to exported functions:

• tidytlg: get_file_name, insert_empty_rows
• rtables.officer: .apply_bold_manual, .apply_alignments, .extract_font_and_size_from_flx

Checks

• (Have you updated the changelog.md ?)