Fix compiler bug with nested optional arguments

This commit fixes compiler bug where it fails when optional values are
compiled into absent values in nested calls.

- Throw exception with more context for easier future debugging.
- Add better validation of argument values for nested calls.
- Refactor `FunctionCallCompiler` for better clarity and modularize it
  to make it more maintainable and testable.
- Refactor related interface to not have `I` prefix, and
  function/variable names for better clarity.

Context:

Discovered this issue while attempting to call
`RunInlineCodeAsTrustedInstaller` which in turn invokes `RunPowerShell`
for issue #246. This led to the realization that despite parameters
flagged as optional, the nested argument compilation didn't support
them.

tests/unit/shared/Stubs/ExpressionsCompilerStub.ts

@@ -3,14 +3,14 @@ import { IReadOnlyFunctionCallArgumentCollection } from '@/application/Parser/Sc
 import { scrambledEqual } from '@/application/Common/Array';
 import { ISharedFunction } from '@/application/Parser/Script/Compiler/Function/ISharedFunction';
 import { FunctionCallArgumentCollectionStub } from '@tests/unit/shared/Stubs/FunctionCallArgumentCollectionStub';
+import { StubWithObservableMethodCalls } from './StubWithObservableMethodCalls';
 
-export class ExpressionsCompilerStub implements IExpressionsCompiler {
-  public readonly callHistory = new Array<{
-    code: string, parameters: IReadOnlyFunctionCallArgumentCollection }>();
+export class ExpressionsCompilerStub
+  extends StubWithObservableMethodCalls<IExpressionsCompiler>
+  implements IExpressionsCompiler {
+  private readonly scenarios = new Array<ExpressionCompilationScenario>();
 
-  private readonly scenarios = new Array<ITestScenario>();
-
-  public setup(scenario: ITestScenario): ExpressionsCompilerStub {
+  public setup(scenario: ExpressionCompilationScenario): ExpressionsCompilerStub {
     this.scenarios.push(scenario);
     return this;
   }
@@ -28,7 +28,10 @@ export class ExpressionsCompilerStub implements IExpressionsCompiler {
     code: string,
     parameters: IReadOnlyFunctionCallArgumentCollection,
   ): string {
-    this.callHistory.push({ code, parameters });
+    this.registerMethodCall({
+      methodName: 'compileExpressions',
+      args: [code, parameters],
+    });
     const scenario = this.scenarios.find(
       (s) => s.givenCode === code && deepEqual(s.givenArgs, parameters),
     );
@@ -43,7 +46,7 @@ export class ExpressionsCompilerStub implements IExpressionsCompiler {
   }
 }
 
-interface ITestScenario {
+interface ExpressionCompilationScenario {
   readonly givenCode: string;
   readonly givenArgs: IReadOnlyFunctionCallArgumentCollection;
   readonly result: string;