modules: storage: Remove Memfault FS free space config

The Memfault filesystem free space monitoring configuration
breaks memfault heartbeats when not using the littlefs storage backend.
Removing them to fix the issue.

Signed-off-by: Trond F. Christiansen <trond.christiansen@nordicsemi.no>

Author: Trond-F-Christiansen

app/overlay-memfault.conf

@@ -8,8 +8,7 @@ CONFIG_MEMFAULT=y
 CONFIG_MEMFAULT_HEAP_STATS=y
 CONFIG_MEMFAULT_LOGGING_ENABLE=y
 CONFIG_MEMFAULT_LOGGING_RAM_SIZE=4096
-CONFIG_MEMFAULT_FS_BYTES_FREE_METRIC=y
-CONFIG_MEMFAULT_FS_BYTES_FREE_VFS_PATH="att_storage"
+CONFIG_MEMFAULT_FS_BYTES_FREE_METRIC=n
 CONFIG_MEMFAULT_COREDUMP_FULL_THREAD_STACKS=y
 CONFIG_MEMFAULT_HTTP_DEDICATED_WORKQUEUE_STACK_SIZE=1560
 CONFIG_MEMFAULT_HTTP_PERIODIC_UPLOAD=y