Fix plunker issues found while fixing select field plunker

[Blackbaud-TrevorBurch]

Found while working on #1769

These changes fix the Plunker's for the Infinite Scroll, Sectioned Form, and Toast components.
The Select Field Plunker is fixed via blackbaud/skyux2-docs#142

[codecov-io]

Codecov Report

Merging #1931 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #1931   +/-   ##
======================================
  Coverage     100%    100%           
======================================
  Files         416     416           
  Lines        8757    8757           
  Branches     1292    1292           
======================================
  Hits         8757    8757

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