Autotests: Create helper functions for Atom Properties window (and replace with it nessussary code)

[AlexeyGirin]

Create helper functions for Atom Properties window and replace improper code with them.

You can identify such code using following lines for search:
await page.getByLabel('Label').fill('J%');
await page.getByLabel('Charge').fill('A');
await page.getByLabel('Isotope').fill('b');
await page.getByLabel('Atom').fill('F^^');
await page.getByLabel('Unsaturated').uncheck();
await page.getByLabel('Alias').fill(alias);