Add more `Sendable` conformances to resolve warnings #765

Job	Run time
build-eliza-swiftpm-example	2m 35s
build-eliza-cocoapods-example	1m 19s
build-library-macos	2m 55s
build-library-ios	3m 11s
build-library-tvos	3m 15s
build-library-watchos	3m 11s
build-plugin-and-generate	1m 2s
run-conformance-tests	2m 34s
run-unit-tests	2m 13s
run-swiftlint	10s
validate-license-headers	15s
	22m 40s

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