[chore][Makefile] Remove non-existent CMD_MODS_1 target reference (#39383)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
There is no `CMD_MODS_1` variable in the Makefile. It looks like this
was a reference simply missed in
#37498.
It's not causing any problems but we may as well clean it up.

Author: crobert-1

Makefile

@@ -43,7 +43,7 @@ CONNECTOR_MODS := $(shell find ./connector/* $(FIND_MOD_ARGS) -exec $(TO_MOD_DIR
 INTERNAL_MODS := $(shell find ./internal/* $(FIND_MOD_ARGS) -exec $(TO_MOD_DIR) )
 PKG_MODS := $(shell find ./pkg/* $(FIND_MOD_ARGS) -exec $(TO_MOD_DIR) )
 CMD_MODS_0 := $(shell find ./cmd/[a-z]* $(FIND_MOD_ARGS) -not -path "./cmd/otel*col/*" -exec $(TO_MOD_DIR) )
-CMD_MODS := $(CMD_MODS_0) $(CMD_MODS_1)
+CMD_MODS := $(CMD_MODS_0)
 OTHER_MODS := $(shell find . $(EX_COMPONENTS) $(EX_INTERNAL) $(EX_PKG) $(EX_CMD) $(FIND_MOD_ARGS) -exec $(TO_MOD_DIR) )
 ALL_MODS := $(RECEIVER_MODS) $(PROCESSOR_MODS) $(EXPORTER_MODS) $(EXTENSION_MODS) $(CONNECTOR_MODS) $(INTERNAL_MODS) $(PKG_MODS) $(CMD_MODS) $(OTHER_MODS)