fix: send RC channels with correct CRSF type

cel_crsf_build_rc_frame tagged RC channel frames with 0x01,
which is not a valid CRSF frame type. The TX module's CRSF
parser never recognized these as channel updates, so it had
no RC data to forward over RF and the receiver could never
report link quality.

Use CEL_CRSF_TYPE_RC_CHANNELS (0x16), the spec-correct RC
Channels Packed type. Drop the bogus 0x01 enum value.

tests/test_crsf.c

@@ -193,7 +193,7 @@ void test_build_rc_frame_roundtrip(void) {
 
     cel_crsf_frame frame;
     TEST_ASSERT_EQUAL_INT(0, cel_crsf_frame_parse(&frame, dst, len));
-    TEST_ASSERT_EQUAL_UINT8(CEL_CRSF_TYPE_RC_CHANNELS_PACKED, frame.type);
+    TEST_ASSERT_EQUAL_UINT8(CEL_CRSF_TYPE_RC_CHANNELS, frame.type);
 }
 
 void test_build_ping_frame_null_dst(void) {