Fixed logic to delete the interface from BUFFER_QUEUE (#16687)

Description of PR
The interface from where the queuestats fetched was different from the interface that was deleted from the BUFFER_QUEUE.

Github issue: aristanetworks/sonic-qual.msft#371
This issue is seen after PR: #15688

The issue was that
XML dump is below for context

buffer_queue_to_del = 'Ethernet112|6'
buffer_queues = ['Ethernet112|0-1', 'Ethernet112|2-4', 'Ethernet112|5', 'Ethernet112|6', 'Ethernet112|7', 'Ethernet116|0-1', ...]
buffer_queues_removed = 1
interface  = 'Ethernet68'
When the string 'Ethernet112|6' when split with delimiter "|" the string in 1st index "6" is a substring of "Ethernet68" and it picked as a candidate to delete it from BQ, which is wrong.

Summary:
Fixes # aristanetworks/sonic-qual.msft#371

tests/snmp/test_snmp_queue_counters.py

@@ -126,7 +126,7 @@ def test_snmp_queue_counters(duthosts,
 
     # Get appropriate buffer queue value to delete
     buffer_queues = list(data['BUFFER_QUEUE'].keys())
-    iface_buffer_queues = [bq for bq in buffer_queues if any(val in interface for val in bq.split('|'))]
+    iface_buffer_queues = [bq for bq in buffer_queues if bq.split('|')[0] == interface]
     if iface_buffer_queues:
         buffer_queue_to_del = iface_buffer_queues[0]
     else: