[FedCM] Restore the call to computeAndUpdateAccountListHeight

In https://crrev.com/c/6020805 I removed a call to
computeAndUpdateAccountListHeight that seemed unnecessary.

However, the call is needed to ensure thatthe account list does not
take up more space than we want it to -- without it, with enough
accounts, the bottom sheet will expand to the size of the screen.

This CL restores the call, but puts it in a more logical place.

The only reason the code works at all right now is because the caller
by pure chance calls getHalfHeightRatio before it calls getFullHeightRatio.

R=tanzachary@chromium.org

Bug: 378595303
Change-Id: I0060f815bd99b9b299ed31c963ea96ce73a0c0a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6033283
Auto-Submit: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: Zachary Tan <tanzachary@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Reviewed-by: Zachary Tan <tanzachary@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1385201}