pipeline tail: add caution for duplicate logs using ´read_from_head´

[darth-raijin]

This update improves the docs for the Read_From_Head Tail option, providing a clearer explanation of its behavior and potential impact on log duplication.

Key changes:

• Added a warning about potential duplicate logs when Read_From_Head is enabled while using DB, as Fluent Bit may ignore stored offsets on restart.
• Recommended disabling Read_From_Head in production environments to prevent log duplication issues.
• These clarifications are intended to help users better understand and configure the Read_From_Head option, especially when working in production environments where log duplication must be minimized.