Adjust SSD health check to validate range, not threshold (#21127)

The test now asserts that SSD health is between 0 and 100, instead of the previous, stricter check for >50.
It now ensures the reported health value is sane and falls within the valid range of 0% to 100%.

Author: manish1-arista

tests/platform_tests/cli/test_show_platform.py

@@ -543,7 +543,8 @@ def test_show_platform_ssdhealth(duthosts, enum_supervisor_dut_hostname):
 
         if key == "Health":
             health_float_value = float(line_data.strip("%"))
-            pytest_assert(health_float_value > 50.0, "SSD health is '{}', SSD replacement required".format(line_data))
+            pytest_assert(0.0 <= health_float_value <= 100.0,
+                          "SSD health value '{}' is outside the expected 0-100 range".format(health_float_value))
 
         if key == "Temperature":
             temp_float_value = float(line_data.strip("C"))