show proper error message when saving query fails

[madkoo]

This pull request includes modifications to improve the functionality and maintainability of the codebase. The most important changes include replacing function calls and modifying return types in multiple files related to the query editor.

Main changes:

• extension/scripts/wiqlEditor/importExport.ts: Modified the saveQuery function to replace the save function call with the handleSaveResult function call and changed the return type. [1] [2]
• extension/scripts/queryEditor/queryDialog.ts: Added a comment and refactored a function call in the save function, and added a check for result being null or undefined and throwing an error in the handleSaveResult function. [1] [2]
• extension/scripts/queryEditor/queryEditor.ts: Replaced the save import statement and function call with handleSaveResult. [1] [2]