Roll Flutter Engine from eb5d5c66a83e to 7bf93bb919d9 (2 revisions) (#136098)

https://github.com/flutter/engine/compare/eb5d5c66a83e...7bf93bb919d9

2023-10-06 aam@google.com [fuchsia] Remove hardcoded fuchsia-imported packages 2.12 sdk version (flutter/engine#46629)
2023-10-06 kjlubick@users.noreply.github.com Add Base64::EncodedSize to tidy up allocations (flutter/engine#46624)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC chinmaygarde@google.com,rmistry@google.com,zra@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

bin/internal/engine.version

-eb5d5c66a83e5073262405452a715adf4d37f7d1
+7bf93bb919d9e0de92a672177f112df07989e02e