Turn ForceLoad back on, now that the archive has no duplicates

[jcant0n]

Both settings were tried against a real link. This is the one that works.

Without it, the linker keeps only the members something references, and every entry point here is reached from managed code rather than from native. The application built, weighed 30 MB, and did not define cesium_async_system_create at all — the member carrying it had been dropped. A P/Invoke into it would have failed on a device, in somebody else's application, long after every build went green.

With it, the link used to die on duplicate symbols, because the archive carried libjpeg.a beside libturbojpeg.a and libwebpdecoder.a beside libwebp.a. That is now fixed where it belonged — in the merge in CesiumC#19, which no longer takes archives nothing links. The archive went from 61.0 MB across 143 archives to 59.9 MB across 141, and both iOS legs build there.

The smoke leg is what made this a measurement rather than an argument

It reads the built executable and fails if cesium_async_system_create is not among its defined symbols. That is exactly how the dropped member was found, and it is why flipping this back is a one-line change rather than a hope.

Needs the CesiumC release to be re-cut first, which is in flight; the new archive is what makes ForceLoad safe.

[github-actions]

API gate: additive

Every symbol that existed still exists, unchanged. Nothing that compiled before stops compiling.

Target framework	Added	Removed
net10.0-ios	+0	-0
net10.0	+0	-0

_{Enum and constant values are part of the measured surface: a renumbering keeps compiling and sends the wrong number to the driver, so it counts as a removal.}