Disable autolayout rcparam when constructing Facet/PairGrid

[mwaskom]

This prevents matplotlib from doing a naive tight_layout operation that ignores the space the legend needs to occupy.

Closes #2496

[codecov]

Codecov Report

Merging #2571 (f2b0298) into master (ec8fcc9) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head f2b0298 differs from pull request most recent head f5c04ad. Consider uploading reports for the commit f5c04ad to get more accurate results

@@           Coverage Diff           @@
##           master    #2571   +/-   ##
=======================================
  Coverage   97.45%   97.46%           
=======================================
  Files          17       17           
  Lines        6332     6340    +8     
=======================================
+ Hits         6171     6179    +8     
  Misses        161      161           

Impacted Files	Coverage Δ
seaborn/_statistics.py	100.00% <100.00%> (ø)
seaborn/axisgrid.py	95.65% <100.00%> (+0.01%)	⬆️
seaborn/distributions.py	96.37% <100.00%> (ø)

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