[action] [PR:18106] Regex correction for bgp commands in show_tech_cmds.py (sonic-net#295)

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### Description of PR
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The regex is enhanced to capture the logs correctly.
Test failed with error  -
"_Failed: Commands not found for 'bgp_cmds': vtysh(\s+-Ec 'show bgp ipv4
neighbors .* advertised-routes' -Ec 'show bgp ipv4 neighbors .*
routes')+; vtysh(\s+-Ec 'show bgp ipv6 neighbors .* advertised-routes'
-Ec 'show bgp ipv6 neighbors .* routes')+_ "
Summary:
Fixes # (issue)

### Type of change

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- [x] Bug fix
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- [ ] Bug fix
- [ ] Testbed and Framework(new/improvement)
- [ ] New Test case
    - [ ] Skipped for non-supported platforms
- [x] Test case improvement

### Back port request
- [ ] 202012
- [ ] 202205
- [ ] 202305
- [ ] 202311
- [ ] 202405
- [x] 202411

### Approach
#### What is the motivation for this PR?
Test failed with error  -
"_Failed: Commands not found for 'bgp_cmds': vtysh(\s+-Ec 'show bgp ipv4
neighbors .* advertised-routes' -Ec 'show bgp ipv4 neighbors .*
routes')+; vtysh(\s+-Ec 'show bgp ipv6 neighbors .* advertised-routes'
-Ec 'show bgp ipv6 neighbors .* routes')+_ "
#### How did you do it?

#### How did you verify/test it?
Executed test suite and verfiy
#### Any platform specific information?

#### Supported testbed topology if it's a new test case?

### Documentation
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(If it's a new feature, new test case)
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Author: mssonicbld

tests/show_techsupport/tech_support_cmds.py

@@ -115,10 +115,10 @@
     "vtysh{} -c 'show bgp ipv4 labeled-unicast'",
     "vtysh{} -c 'show bgp ipv6 labeled-unicast'",
     "vtysh{} -c 'show bgp mac hash'",
-    re.compile(r"vtysh(\s+-Ec 'show bgp ipv4 neighbors .* advertised-routes' "
-               "-Ec 'show bgp ipv4 neighbors .* routes')+"),
-    re.compile(r"vtysh(\s+-Ec 'show bgp ipv6 neighbors .* advertised-routes' "
-               "-Ec 'show bgp ipv6 neighbors .* routes')+"),
+    re.compile(r"vtysh(?:\s+-n\s+0)?(\s+-Ec 'show bgp ipv4 neighbors .* advertised-routes'(?:\s+-n\s+0)?\s+-Ec"
+               r" 'show bgp ipv4 neighbors .* routes')+"),
+    re.compile(r"vtysh(?:\s+-n\s+0)?(\s+-Ec 'show bgp ipv6 neighbors .* advertised-routes'(?:\s+-n\s+0)?\s+-Ec"
+               r" 'show bgp ipv6 neighbors .* routes')+"),
 
 ]