fix: TABConfigParser.remove_section() is not working read()

TABConfigParser.remove_section() uses interval variable `_proxies`, which is also being deleted if you try to remove some section. Our implementation of `_read` method does not set that `_proxies` variable anyhow.

splunk_add_on_ucc_framework/alert_utils/alert_utils_common/conf_parser.py

@@ -111,6 +111,9 @@ def _read(self, fp, fpname):
                         cursect = self._dict()
                         cursect["__name__"] = sectname
                         self._sections[sectname] = cursect
+                        self._proxies[sectname] = configparser.SectionProxy(
+                            self, sectname
+                        )
                     # So sections can't start with a continuation line
                     optname = None
                 # no section header in the file?