Remove unnecessary import directives

[IndrajeetPatil]

Discovered while thinking about easystats/easystats#379

[codecov]

Codecov Report

Merging #607 (e0687cb) into main (09e3209) will not change coverage.
The diff coverage is 100.00%.

❗ Current head e0687cb differs from pull request most recent head 056506e. Consider uploading reports for the commit 056506e to get more accurate results

@@           Coverage Diff           @@
##             main     #607   +/-   ##
=======================================
  Coverage   90.55%   90.55%           
=======================================
  Files          56       56           
  Lines        3419     3419           
=======================================
  Hits         3096     3096           
  Misses        323      323           

Files Changed	Coverage Δ
R/convert_stat_chisq.R	91.66% <ø> (ø)
R/eta_squared-main.R	95.80% <ø> (ø)
R/cohens_d.R	95.87% <100.00%> (ø)
R/eta_squared-methods.R	89.47% <100.00%> (ø)
R/xtab_diff.R	87.65% <100.00%> (ø)