ci: add elasticsearch dependencies to unit tests workflow

Add .[elasticsearch] extra to install Elasticsearch handler dependencies
(elasticsearch>=7.13.4,<9.0.0 and elasticsearch-dbapi>=0.2.9) during
unit test runs.

Author: richardokonicha

.github/workflows/tests_unit.yml

@@ -131,7 +131,8 @@ jobs:
             .[statsforecast] \
             .[mysql] \
             .[chromadb] \
-            .[mssql]
+            .[mssql] \
+            .[elasticsearch]
           uv pip freeze
           git clone --branch v$(uv pip show mindsdb_sql_parser | grep Version | cut -d ' ' -f 2) https://github.com/mindsdb/mindsdb_sql_parser.git parser_tests