[10.x] Remove warning about schema dumps and in-memory SQLite databases.

[patrickcarlohickman]

The docs have a warning in the "Squashing Migrations" section that schema dumps may not be restored to in-memory SQLite database. However, I believe this issue was resolved in PR #45375, which was released in v9.45.1.

To test this, I ran the following steps in a project that had existing migrations:

1. Place an sqlite schema at: database/schema/sqlite-schema.dump

CREATE TABLE IF NOT EXISTS "migrations" ("id" integer not null primary key autoincrement, "migration" varchar not null, "batch" integer not null);

2. Update the .env file with the following values:

DB_CONNECTION=sqlite
DB_DATABASE=:memory:

3. Run the migration (php artisan migrate) and see them all succeed.

According to a previous issue #35162, this normally would have failed with all the migration files stating "SQLSTATE[HY000]: General error: 1 no such table: migrations". However, it appears to be working fine now.