fix(e2e): remove stale symlink requirement from 10_env_command.sh

The test only calls `mcpp self env`, checks directory/file existence,
and runs grep. It neither sources _inherit_toolchain.sh nor performs
any symlink operations directly. The `# requires: symlink` tag caused
the test to be incorrectly skipped on Windows even though it has no
symlink dependency.

Author: Sunrisepeak

tests/e2e/10_env_command.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# requires: symlink
+# requires:
 # `mcpp env` initializes $MCPP_HOME and prints expected layout.
 set -e