Convert default command template values into ShellQuotedString format

[danegsta]

If a task command template has the default value, this attempts to parse it and convert into a ShellQuotedString format so that VSCode will perform appropriate argument escaping for the selected shell. The current logic will only run if a task is configured with the default value as the current parsing logic assumes certain conditions that may not be true for a user customized value.

This should resolve #4291.

[bwateratmsft]

Synced offline, this needs some adjustment:

vscode-docker/src/commands/images/buildImage.ts

Lines 52 to 69 in 62dcfc5

	if (tagRegex.test(terminalCommand.command)) {
	const absFilePath: string = path.join(rootFolder.uri.fsPath, dockerFileItem.relativeFilePath);
	const dockerFileKey = `buildTag_${absFilePath}`;
	const prevImageName: string | undefined = ext.context.workspaceState.get(dockerFileKey);
	// Get imageName based previous entries, else on name of subfolder containing the Dockerfile
	const suggestedImageName = prevImageName || getValidImageNameFromPath(dockerFileItem.absoluteFolderPath, 'latest');
	// Temporary work-around for vscode bug where valueSelection can be messed up if a quick pick is followed by a showInputBox
	await delay(500);
	addImageTaggingTelemetry(context, suggestedImageName, '.before');
	const imageName: string = await getTagFromUserInput(context, suggestedImageName);
	addImageTaggingTelemetry(context, imageName, '.after');
	await ext.context.workspaceState.update(dockerFileKey, imageName);
	terminalCommand.command = terminalCommand.command.replace(tagRegex, imageName);
	}