ensure the windowConfig window dimensions uses inherit (#7511)

## Summary

- a follow-up to #7440 to address
    - #3303
    - #6277

I'll also cherry-pick this to `main` once merged.

### Implementation

We need to explicitly set the windowConfig to
`window.newWindowDimensions = 'inherit'` because the default settings
aren't read anywhere otherwise.

Similar handling can be found in:
-
https://github.com/posit-dev/positron/blob/66236dbf0e9dd1739915979cdd152adc587810c6/src/vs/platform/launch/electron-main/launchMainService.ts#L159-L173
-
https://github.com/posit-dev/positron/blob/83cc85cee46e2d53a1eadcb86f8cfb9704c1e5a4/src/vs/platform/windows/electron-main/windowsMainService.ts#L985-L999

## QA Notes

Please try this out on machines with different screen sizes and
operating systems!

Make sure you don't already have `window.newWindowDimensions = inherit`
set in your user settings JSON, to ensure that the setting is pulling in
our new default value instead of pulling from your user setting (...not
speaking from experience or anything 😅)

Please also try testing:
- with no user settings that are for `window`, e.g. comment out/remove
any settings that start with `window.`
- with at least one user setting that is for `window`, such as
`"window.openFoldersInNewWindow": "on"`

Author: sharon-wang

src/vs/platform/windows/electron-main/windowsStateHandler.ts

@@ -269,7 +269,10 @@ export class WindowsStateHandler extends Disposable {
 
 	getNewWindowState(configuration: INativeWindowConfiguration): INewWindowState {
 		const state = this.doGetNewWindowState(configuration);
-		const windowConfig = this.configurationService.getValue<IWindowSettings | undefined>('window');
+		// --- Start Positron ---
+		// const windowConfig = this.configurationService.getValue<IWindowSettings | undefined>('window');
+		const windowConfig = this.getWindowSettingsConfig();
+		// --- End Positron --
 
 		// Fullscreen state gets special treatment
 		if (state.mode === WindowMode.Fullscreen) {
@@ -385,7 +388,10 @@ export class WindowsStateHandler extends Disposable {
 		state.y = Math.round(displayToUse.bounds.y + (displayToUse.bounds.height / 2) - (state.height! / 2));
 
 		// Check for newWindowDimensions setting and adjust accordingly
-		const windowConfig = this.configurationService.getValue<IWindowSettings | undefined>('window');
+		// --- Start Positron ---
+		// const windowConfig = this.configurationService.getValue<IWindowSettings | undefined>('window');
+		const windowConfig = this.getWindowSettingsConfig();
+		// --- End Positron ---
 		let ensureNoOverlap = true;
 		if (windowConfig?.newWindowDimensions) {
 			if (windowConfig.newWindowDimensions === 'maximized') {
@@ -418,6 +424,26 @@ export class WindowsStateHandler extends Disposable {
 		return state;
 	}
 
+	// --- Start Positron ---
+	/**
+	 * Retrieves the window settings configuration object from the configuration service and ensures
+	 * that the newWindowDimensions property is updated with Positron's default config changes.
+	 * @returns The window settings configuration object, or undefined if it doesn't exist.
+	 */
+	private getWindowSettingsConfig() {
+		const windowConfig = this.configurationService.getValue<IWindowSettings | undefined>('window');
+		const updatedWindowConfig = {
+			...(windowConfig ? windowConfig : {}),
+			// We've changed the default value of newWindowDimensions to 'inherit' in Positron, so we need to
+			// set it to 'inherit' if it unset in the config, as we'll fallthrough to the default window state otherwise.
+			// Search for `window.newWindowDimensions` in src/vs/workbench/electron-sandbox/desktop.contribution.ts
+			// for the default configuration.
+			newWindowDimensions: windowConfig?.newWindowDimensions || 'inherit',
+		};
+		return updatedWindowConfig;
+	}
+	// --- End Positron ---
+
 	private ensureNoOverlap(state: IWindowUIState): IWindowUIState {
 		if (this.windowsMainService.getWindows().length === 0) {
 			return state;