chore: remove unneeded registration (#268)

Tripped over this in rules_ts where I copied the snippet, and the registration leaked into userland.

It's enough to add the tag_class, then rules_swc reads it when it registers.

e2e/smoke/MODULE.bazel

@@ -12,6 +12,3 @@ swc.toolchain(
     name = "swc",
     swc_version = "v1.3.78",
 )
-use_repo(swc, "swc_toolchains")
-
-register_toolchains("@swc_toolchains//:all")