Current implementation Panics if accessing Default NVS partition

[michaelvanstraten]

The current implementation of the custom attribute descriptor appears to indefinitely reference the EspDefaultNvsPartition. This leads to a panic when someone else attempts to access the mentioned default partition.

This issue arises from the lazy initialization of a static variable (STORAGE) in src/gatt_server/custom_attributes.rs, which retains a Mutex lock until itself is dropped. I am working on resolving this problem promptly and wanted to inform anyone else who may encounter the same issue.