Create tag for BS Stage 2 lockloss

[Resulting from a conversation with Jim] Due to an increase in locklosses around the TURN_ON_BS_STAGE_2 ISC_LOCK state (states: 104, 105), we would like to create a tag that checks if the lockloss occurs when the SEI_BS Guardian node is transitioning (state: -19).

The ASC/LSC channels we already plot should be sufficient for analyzing these locklosses. Progress in fixing this will be gauged by tag prevalence before/after changes are made to the SEI Guardian.