feat: add missing CLI commands (alter_collection_function, has_database, has_alias, create_field_schema, server_type)

[nameczz]

Summary

• Adds 5 CLI commands for pymilvus APIs that had Client methods but no CLI exposure
• Each command has corresponding integration tests
• Updated utils.py autocomplete

New Commands

Command	API	File
alter_collection_function -c <coll> -f <func>	alter_collection_function	collection_client_cli.py
has_database -db <name>	has_database	database_client_cli.py
has_alias -a <name>	has_alias	alias_client_cli.py
create_field_schema -f <name> -t <type>	create_field_schema	collection_client_cli.py
server_type	get_server_type	helper_client_cli.py