Fix test_sysuptime failure (#16528)

* The change strips comma (if present) from py_gnmicli proc/uptime output before
  converting to float

What is the motivation for this PR?
Fix broken test

How did you do it?
Fix format parsing before type conversion

How did you verify/test it?
Tested on 7050cx3

Author: opcoder0

tests/telemetry/test_telemetry.py

@@ -230,7 +230,7 @@ def test_sysuptime(duthosts, enum_rand_one_per_hwsku_hostname, ptfhost, gnxi_pat
     for line_info in system_uptime_info:
         if "total" in line_info:
             try:
-                system_uptime_1st = float(line_info.split(":")[1].strip())
+                system_uptime_1st = float(line_info.split(":")[1].strip().rstrip(','))
                 found_system_uptime_field = True
             except ValueError as err:
                 pytest.fail(