refactor(example_data): replace the way the birth_names data is loaded to DB (#18060)

* refactor: replace the way the birth_names data is loaded to DB

* fix failed unit test

* fix failed unit test

* fix failed tests

* fix pass wrong flag of support datetime type

* remove unused fixture

tests/example_data/data_generator/string_generator.py

@@ -0,0 +1,33 @@
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing,
+#  software distributed under the License is distributed on an
+#  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+#  KIND, either express or implied.  See the License for the
+#  specific language governing permissions and limitations
+#  under the License.
+from random import choices, randint
+
+
+class StringGenerator:
+    _seed_letters: str
+    _min_length: int
+    _max_length: int
+
+    def __init__(self, seed_letters: str, min_length: int, max_length: int):
+        self._seed_letters = seed_letters
+        self._min_length = min_length
+        self._max_length = max_length
+
+    def generate(self) -> str:
+        rv_string_length = randint(self._min_length, self._max_length)
+        randomized_letters = choices(self._seed_letters, k=rv_string_length)
+        return "".join(randomized_letters)