fix: Explicitly set TLS backends

Dependency updates mean we have to set a custom TLS backend sooner.
Also some groundwork for being able to use aws-lc in future

src/api/Cargo.toml

@@ -29,10 +29,6 @@ gzip_compression = [
 	"conduwuit-service/gzip_compression",
 	"reqwest/gzip",
 ]
-http3 = [
-	"conduwuit-core/http3",
-	"conduwuit-service/http3",
-]
 io_uring = [
 	"conduwuit-service/io_uring",
 ]