Migration #77 would set the `TokenListController.tokensChainsCache`
state to `undefined` if it wasn't already set to anything when that
migration was run. This is probably harmless except that it results
in Sentry errors during migrations, and it results in that property
having a value (at least temporarily) that doesn't match its type.
Migration #77 has been updated to prevent this property from being
set to `undefined` going forward. A new migration has been added to
delete this value for any users already affected by this problem. The
new migration was named "92.1" so that it could run after 92 but before
93, to make backporting this to v10.34.x easier (v10.34.x is currently
on migration 92). "92.1" is still a valid number so this should work
just as well as a whole number.
