ui: Add a transaction contention event visualizer to Advanced Debug

**Is your feature request related to a problem? Please describe.**
The `crdb_internal.transaction_contention_events` virtual table surfaces transaction contention events including information about the blocking and waiting transaction. This information lends itself well for a directed graph visualization, where the transactions are nodes and the contention events are edges in a directed graph.

**Describe the solution you'd like**
For a breather week project, we want to add a new page to the Advanced Debug page on the DB Console that visualizes transaction contention events in the form of a network graph. Additionally, the graph will be able to show the user more information about the transactions in contention as well as statement statistics.

**Describe alternatives you've considered**
N/A

**Additional context**
N/A

Jira issue: CRDB-22373