chore: raise compressed layer size limit to 10 MB

Leave ~700 KB of headroom over the current largest layer (py3.14-amd64,
9538 KB) so the next few ddtrace releases don't immediately re-block CI.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: joeyzhao2018

scripts/check_layer_size.sh

@@ -8,7 +8,7 @@
 # Compares layer size to threshold, and fails if below that threshold
 
 set -e
-MAX_LAYER_COMPRESSED_SIZE_KB=$(expr 9 \* 1024 + 512)     # 9728 KB
+MAX_LAYER_COMPRESSED_SIZE_KB=$(expr 10 \* 1024)     # 10240 KB
 MAX_LAYER_UNCOMPRESSED_SIZE_KB=$(expr 25 \* 1024)   # 25600 KB