refactor: Improve QuizScreen layout and choice presentation

This commit refactors the `QuizScreen` to use a `Column` instead of a `LazyColumn` for its main layout, improving the positioning and sizing of elements. It also introduces an `EvenGrid` composable for displaying choices, ensuring they are evenly distributed.

Key changes:

- **QuizScreen.kt:**
    - Changed the main layout from `LazyColumn` to `Column`.
    - Toolbar, QuestionContent, Choices, Timer, and ContinueButton are now direct children of the `Column`.
    - `QuestionContent` now uses `fillMaxHeight(0.5f)` to take up half the available height.
    - `Choices` composable now uses `weight(1f)` to fill remaining space.
    - Removed `animateContentSize` and `animateItem` modifiers.
    - Refactored how individual UI sections (toolbar, question, choices, timer, continue button) are structured within the main `Column`.
- **components/EvenGrid.kt:**
    - Added a new reusable `EvenGrid` composable that arranges items into a grid with a specified number of columns, ensuring even distribution.
- **components/Choices.kt:**
    - Replaced `FlowRow` with the new `EvenGrid` composable to display choices.
    - `ChoiceItem` now uses `fillMaxHeight()` within the `EvenGrid` cell.
    - Removed explicit height setting for `ChoiceItem`'s `Box`.
- **components/QuestionContent.kt:**
    - `AsyncImage` within `QuestionContent` now uses `weight(1f)` instead of `heightIn(min = 200.dp)`.
- **components/TimerBar.kt:**
    - Removed `coerceIn(0f, 1f)` for `progress` in `fillMaxWidth` as progress should already be within this range.
- **QuizScreenViewModel.kt & domain/models/Question.kt:**
    - Made `Question.choices` non-nullable (`List<Choice>`) and updated the mapper and ViewModel to reflect this. This simplifies null checks for `currentQuestion.choices`.
    - Accessing `quizState.quiz.questions[currentQuestionIndex]` directly instead of `getOrNull` as the index should always be valid.
- **data/mappers/QuizMapper.kt:**
    - Updated `QuestionDto.toDomain()` to return `orEmpty()` for choices, ensuring a non-null list.

domain/src/main/kotlin/dev/adriankuta/kahootquiz/domain/models/Question.kt

@@ -10,7 +10,7 @@ data class Question(
     val time: Duration?,
     val points: Boolean? = null,
     val pointsMultiplier: Int?,
-    val choices: List<Choice>?,
+    val choices: List<Choice>,
     val layout: String? = null,
     val image: String? = null,
     val imageMetadata: ImageMetadata?,