fix(stackPrefetch): Cleans up stack prefetching order logic

[alexfreska]

• Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  Bug fix / cleanup

• What is the current behavior? (You can also link to an open issue here)

Changes in #1074 accidentally reversed the stack prefetching queue of imageIds returned from the prioritization algorithm. This was later fixed in #1089 here by passing the addToBeginning flag to the requestPoolManager. This PR removes the array reversal which removes the need for the flag as well.

I noticed this issue because I was still running on v4.2.0, the addToBeginning flag fixes things in more recent versions but I thought it was worth cleaning up!

• What is the new behavior (if this is a feature change)?
  N/A

• Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)
  N/A

• Other information:

[codecov]

Codecov Report

Merging #1132 into master will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master    #1132   +/-   ##
=======================================
  Coverage   18.97%   18.97%           
=======================================
  Files         282      282           
  Lines        8404     8404           
  Branches     1422     1422           
=======================================
  Hits         1595     1595           
  Misses       5653     5653           
  Partials     1156     1156           

Impacted Files	Coverage Δ
src/stackTools/stackPrefetch.js	5.67% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3410842...27def2d. Read the comment docs.