Add `customTitle` field to `InstanceInfo`.

This change introduces a new `@Nullable String customTitle` field to the `InstanceInfo` class. The constructor has been updated to include this new parameter, and all existing calls to the `InstanceInfo` constructor have been updated to pass `null` for the new `customTitle` argument.

Bug: 438495397
Change-Id: Ia308fe8f141253b4a21d8a60b74168bdd631add6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6875717
Reviewed-by: Aishwarya Rajesh <aishwaryarj@google.com>
Reviewed-by: Sirisha Kavuluru <skavuluru@google.com>
Commit-Queue: Ryan Thomas <rathomas@google.com>
Cr-Commit-Position: refs/heads/main@{#1505959}