Refactor to enforce strictNullChecks

This commit applies `strictNullChecks` to the entire codebase to improve
maintainability and type safety. Key changes include:

- Remove some explicit null-checks where unnecessary.
- Add necessary null-checks.
- Refactor static factory functions for a more functional approach.
- Improve some test names and contexts for better debugging.
- Add unit tests for any additional logic introduced.
- Refactor `createPositionFromRegexFullMatch` to its own function as the
  logic is reused.
- Prefer `find` prefix on functions that may return `undefined` and
  `get` prefix for those that always return a value.

src/application/Parser/Script/Compiler/Expressions/Expression/Expression.ts

@@ -15,19 +15,10 @@ export class Expression implements IExpression {
     public readonly evaluator: ExpressionEvaluator,
     parameters?: IReadOnlyFunctionParameterCollection,
   ) {
-    if (!position) {
-      throw new Error('missing position');
-    }
-    if (!evaluator) {
-      throw new Error('missing evaluator');
-    }
     this.parameters = parameters ?? new FunctionParameterCollection();
   }
 
   public evaluate(context: IExpressionEvaluationContext): string {
-    if (!context) {
-      throw new Error('missing context');
-    }
     validateThatAllRequiredParametersAreSatisfied(this.parameters, context.args);
     const args = filterUnusedArguments(this.parameters, context.args);
     const filteredContext = new ExpressionEvaluationContext(args, context.pipelineCompiler);