auth: capture boost::regex_error not std::regex_error

in a3db5401, we introduced the TLS certi authenticator, which is
configured using `auth_certificate_role_queries` option . the
value of this option contains a regular expression. so there are
chances the regular expression is malformatted. in that case,
when converting its value presenting the regular expression to an
instance of `boost::regex`, Boost.Regex throws a `boost::regex_error`
exception, not `std::regex_error`.

since we decided to use Boost.Regex, let's catch `boost::regex_error`.

Refs a3db5401
Fixes scylladb/scylladb#20941
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>

Closes scylladb/scylladb#20942

auth/certificate_authenticator.cc

@@ -76,7 +76,7 @@ auth::certificate_authenticator::certificate_authenticator(cql3::query_processor
                     continue;
                 } catch (std::out_of_range&) {
                     // just fallthrough
-                } catch (std::regex_error&) {
+                } catch (boost::regex_error&) {
                     std::throw_with_nested(std::invalid_argument(fmt::format("Invalid query expression: {}", map.at(cfg_query_attr))));
                 }
             }