test: optimize tests by adding shared utility functions

[YaelChen]

Description

I added the previous tests (verify an API call for gtfs_agencies, verify the dateFrom parameter is a recent date) as functions under utils, so there won't be unnecessary code duplication.

[github-actions]

Preview: https://s3.amazonaws.com/noam-gaash.co.il/14957574552/open-bus/562/index.html
Preview Storybook: https://s3.amazonaws.com/noam-gaash.co.il/14957574552/open-bus/562/storybook/index.html
Test Report (if available): 'https://s3.amazonaws.com/noam-gaash.co.il/14957574552/open-bus/159b3876f607fdee9cc96aa8e1b0cd1093fa8cd5/test-results/index.html'

[NoamGaash]

some ideas -

1. You can use expect.extend to create custom assertions like expect(page).toGetRequest('gtfs_agencies/list')
2. I think it could be preferable to separate navigation commands (goto, click and so on) from the assertion commands - maybe it can be something like:

const callAssertion = expect(page).toCall('gtfs_agencies/list')
await page.goto('/')
await page.getByRole('link', { name: 'נסיעות שלא בוצעו', exact: true }).click()
await page.getByLabel('חברה מפעילה').click()
await callAssertion

what do you think?

[NoamGaash]

It looks great! Thanks, and apologies for taking the time with the review 🙏