Revert BUILD_ID back to MAIN.

Bug: 370570306
Merged-In: If2eaf6149808bcc3d5330933bb969adc3d0dbed0
Change-Id: I30da235f86ec3a131ade2342b87f6e9f2313c514
diff --git a/core/build_id.mk b/core/build_id.mk
index 844e51a..bed839f 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -18,4 +18,4 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-BUILD_ID=AP4A.240925.013
+BUILD_ID=MAIN