Enhance systems_mount_point_state test

[RishabhAgarwal-2001]

Description

The current implementation of the system mount point state test lacks the ability to validate the dynamic accuracy of file system telemetry. Currently, the test only retrieves and verifies the static state of the file system without confirming that telemetry values update correctly in response to file system changes

Proposed Workflow

To ensure that telemetry accurately reflects real-time changes, the test should be updated to include the following functional validation:

1. File Creation & Validation: The test should write a file to a known writable location on the device. Following this operation, it must verify through state telemetry that the file system's utilized and available size values reflect the change.
2. Cleanup & Verification: The test must delete the created file and confirm that the telemetry reports the restored capacity of the file system.

Implementation Challenges & Considerations

• Vendor-Specific Paths: Different vendors utilize different mount points for writable storage (e.g., /misc/config: or /0/cpu0/harddisk: for Cisco, and /mnt/flash: for Arista)
• Vendor Agnosticism: There is a concern that hardcoding specific mount points will make the test highly dependent on vendor-specific implementation details, potentially leading to future breakages if those details change
• Restricted Mount Points: Certain mount points reported by telemetry may have a reported size of zero or may not support file creation/deletion (e.g., FTP mount points on Cisco devices)