Updated content to reflect the new Alert view and Alert list

## Change Updated content to reflect the new Alert view and Alert list. The following changes have been made to Alert view: * New Overview and Alert History tabs. The Overview section provides a snapshot of important alert information. This is separate from the History tab to clearly differentiate between alert investigation and audit area. * Detection widget now has a _view other alerts from this rule_ button to get fast access to more alerts that came from this rule. Users can pivot to other alerts from this rule. * Updated information on how to close an alert and change alert status. * Updated information on how to adjust the time range. * Updated information on how to apply single and multiple filters. The following changes have been made to Alert list: * Expanded columns to include Risk Score and Tags. This helps users to focus on and prioritize high-risk and critical security findings. * _Ingestion Time_ and _Last Modified_ were also added to Alert List. * Users can now customize columns in the Alert list, add or remove columns from the table. * Expanded filters to include OR and AND operators to allow more complex filtering. * Updated information on how to refresh Alert List. These changes are documented in [Investigate an alert](https://cloud.google.com/chronicle/docs/investigation/investigate-alert) and [View Alerts and IOCs](https://cloud.google.com/chronicle/docs/investigation/alerts-iocs).