buffer: remove unused param from copyActual

[gurgunday]

Follow up to #61721

We added this quirky parameter in #60399 when implementing an optimization to Buffer.concat and Buffer.copy with the intention of eventually removing it when .concat used TypedArrayPrototypeSet in all cases

The parameter was only used in one place until it was removed in #61721:

https://github.com/nodejs/node/pull/61721/changes#diff-3c2cd5c512dd026a7765b6b2ae3f85785d3b7ea3795e11949892b7b73beee630L635

[richardlau]

This change is being made as part of #62032.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.64%. Comparing base (6a3d358) to head (ce5f8c4).
⚠️ Report is 594 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #62042 +/- ##
==========================================
+ Coverage 89.58% 89.64% +0.06% 
==========================================
Files 674 676 +2 Lines 205159 206240 +1081 Branches 39352 39506 +154 ==========================================
+ Hits 183792 184894 +1102 + Misses 13583 13465 -118 - Partials 7784 7881 +97 

Files with missing lines	Coverage Δ
lib/buffer.js	99.16% <100.00%> (ø)

... and 129 files with indirect coverage changes

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[gurgunday]

@richardlau PTAL, that PR is closed for now

[github-actions]

Failed to start CI

 ⚠ No approving reviews found
✘ Refusing to run CI on potentially unsafe PR

https://github.com/nodejs/node/actions/runs/22575987214

[gurgunday]

Cc @ChALkeR maybe for a review

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/73294/

[trivikr]

@gurgunday Can you please resolve conflicts and force push?

[gurgunday]

It's resolved