chore(deps): exclude pylint group entirely (astroid/pylint)

Group PRs are all-or-nothing. Dependabot's pylint group pairs astroid 4.1.2
with pylint 4.0.6, but pylint 4.0.6 requires astroid<=4.1.dev0, so the pair
is unresolvable. Rather than partially apply the group with an astroid
workaround, leave the whole group out (astroid/pylint stay at main values)
so it remains a clean standalone Dependabot PR.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jingjingjia-ms

requirements-dev.txt

@@ -1,7 +1,7 @@
 aiohttp==3.14.1
 aiosignal==1.4.0
 anyio==4.13.0
-astroid==4.0.4
+astroid==4.0.2
 async-timeout==5.0.1
 attrs==26.1.0
 azure-core==1.41.0
@@ -55,7 +55,7 @@ platformdirs==4.10.0
 portalocker==2.10.1
 pycparser==3.0
 PyJWT==2.13.0
-pylint==4.0.6
+pylint==4.0.5
 pyproject_hooks==1.2.0
 python-dateutil==2.9.0.post0
 requests==2.34.2