Update broken links in csharp SDK README (#4952) #22499

Job	Run time
Lints	2m 28s
Check CI command docs	26s
Build and test wasm bindings	4m 36s
Docs build	2m 27s
TypeScript - Tests	4m 22s
Test spacetimedb-update flow (x86_64-pc-windows-msvc)	5m 36s
Check that packages are publishable	5m 9s
Test spacetimedb-update flow (aarch64-apple-darwin)	2m 0s
Test spacetimedb-update flow (x86_64-unknown-linux-gnu)	1m 7s
Test spacetimedb-update flow (aarch64-unknown-linux-gnu)	48s
Check smoketests/mod.rs is complete	11m 25s
Check CLI docs	2m 5s
Verify global.json files are symlinks	1m 4s
version_upgrade_check	9m 50s
Unreal Engine Tests	0s
csharp-testsuite	7m 3s
Test Suite	25m 45s
unity-testsuite	7m 0s
Internal Tests	37m 56s
Smoketests (Linux)	12m 11s
Smoketests (Windows)	29m 46s
	2h 53m 4s

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