stories15M : revert training context to 128

Updated metadata:
* **llama.context_length**: 128

tinyllamas/stories15M-q4_0.gguf

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:696f4aeb78402421f905d60ae7a673ad907e86bef5619a3393241157c8b0e47a
+oid sha256:66967fbece6dbe97886593fdbb73589584927e29119ec31f08090732d1861739
 size 19077344