Splat build.ps1 arguments as a hashtable so the CI dispatch inputs work

[Rafael-SOWNet]

The problem

CI Build's workflow_dispatch inputs cannot be used. Setting any of them to false fails the
run immediately:

build.ps1: A positional parameter cannot be found that accepts argument '-SkipCoverage'.

$buildArguments is an array, and PowerShell array splatting binds positionally.
Build/build.ps1 declares only switches (SkipTests, SkipCoverage, SkipPack,
SkipArchive) and no positional parameters, so the first element has nowhere to bind.

Only the all-defaults path works, because that leaves the array empty and splats nothing. That
is why push and pull_request have never hit this — neither populates the inputs, so every
value resolves true and every branch of the if is skipped.

The fix

Splat a hashtable instead, which binds by parameter name.

Why it is worth fixing

Beyond the inputs doing what they say: dispatching this workflow by hand is the only way to get
a full matrix run on a branch that has no pull request open, and it is the practical way for a
first-time contributor to produce CI evidence while pull_request runs are gated behind
approval. Right now that path only works if you want the slowest possible run — full coverage,
pack and archive — because asking to skip any of it is what breaks it.

Validation

Same workflow, same inputs, before and after. Both runs on my fork.

Before — ci.yml exactly as it is on master, dispatched with
run_tests=true, collect_coverage=false, pack_nugets=false, upload_artifacts=false:

https://github.com/Rafael-SOWNet/UnitsNet/actions/runs/31124240783 — failure, at
Build selected components, with the message quoted above.

After — this branch, identical inputs:

https://github.com/Rafael-SOWNet/UnitsNet/actions/runs/31136388644 — success.

Passed! - Failed: 0, Passed: 52560, Skipped: 16, Total: 52576
Passed! - Failed: 0, Passed:  1731, Skipped:  0, Total:  1731
Passed! - Failed: 0, Passed:  1731, Skipped:  0, Total:  1731
Passed! - Failed: 0, Passed:   213, Skipped:  0, Total:   213
Passed! - Failed: 0, Passed:   241, Skipped:  0, Total:   241
Passed! - Failed: 0, Passed:     1, Skipped:  0, Total:     1
Passed! - Failed: 0, Passed:     1, Skipped:  0, Total:     1

Upload coverage to Codecov, Upload artifacts and Upload NuGet packages were all skipped,
which is what the inputs asked for and what previously could not be expressed.

What this does not do

No change to Build/build.ps1, to the default behaviour of push or pull_request, or to any
other workflow. .github/workflows/unitsnet-modular-ci.yml uses a plain run: and is
unaffected.