feat: Expand flame_lint to respect required pub.dev checks (#3139)

Expand flame_lint to respect required pub.dev checks.

We are currently losing pub points due to lint violations:


![image](https://github.com/flame-engine/flame/assets/882703/b6a6cf0a-aea1-4e75-b1cb-611d5f8a154c)

Turns out `flame_lint` does not respect lints/core which is being
enforced now by pub.

This adds that as a dependency on `flame_lint`, updates `flutter_lint`
for the packages that use that, and fix all existing violations (luckily
very few).

This change will ensure that us and everyone else who uses `flame_lint`
get all the points they deserve on pub. We can consider expanding to
`lints/recommended` in the future, but that is definitely not a
requirement at this stage (and a much bigger change).

doc/tutorials/platformer/app/lib/ember_quest.dart

@@ -57,19 +57,19 @@ class EmberQuestGame extends FlameGame
   void loadGameSegments(int segmentIndex, double xPositionOffset) {
     for (final block in segments[segmentIndex]) {
       final component = switch (block.blockType) {
-        GroundBlock => GroundBlock(
+        GroundBlock _ => GroundBlock(
             gridPosition: block.gridPosition,
             xOffset: xPositionOffset,
           ),
-        PlatformBlock => PlatformBlock(
+        PlatformBlock _ => PlatformBlock(
             gridPosition: block.gridPosition,
             xOffset: xPositionOffset,
           ),
-        Star => Star(
+        Star _ => Star(
             gridPosition: block.gridPosition,
             xOffset: xPositionOffset,
           ),
-        WaterEnemy => WaterEnemy(
+        WaterEnemy _ => WaterEnemy(
             gridPosition: block.gridPosition,
             xOffset: xPositionOffset,
           ),