fix: Splat container extension calling dispose on finalize

[glennawatson]

The finalize is meant for when the container registrations are complete and allow some containers to mark themselves as immutable.

In the current version we are disposing which will cause a new splat container to be registered, wiping out out registrations.

[codecov]

Codecov Report

Merging #448 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #448   +/-   ##
=======================================
  Coverage   66.82%   66.82%           
=======================================
  Files          70       70           
  Lines        3946     3946           
  Branches      394      394           
=======================================
  Hits         2637     2637           
  Misses       1237     1237           
  Partials       72       72

Impacted Files	Coverage Δ
.../Platforms/ServiceLocationDrawingInitialization.cs	0% <ø> (ø)

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