Improved validating URLs

[grzesiek2010]

Closes #4900

This issue has been partially fixed in https://github.com/getodk/collect/pull/5154 so now on master there is no crash like described in the issue. The improvement here is that wrong URLs like the one from the issue should be not allowed at all.

What has been done to verify that this works as intended?

I've verified the fix manually and improved automated tests.

Why is this the best possible solution? Were any other approaches considered?

There is not much to discuss here. I've just used better validators as discussed in the issue.

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

This should just fix the issue.

Do we need any specific form for testing your changes? If so, please attach one.

No.

Does this change require updates to documentation? If so, please file an issue here and include the link below.

No.

Before submitting this PR, please make sure you have:

• [x] run ./gradlew checkAll and confirmed all checks still pass OR confirm CircleCI build passes and run ./gradlew connectedDebugAndroidTest locally.
• [x] verified that any code or assets from external sources are properly credited in comments and/or in the about file.
• [x] verified that any new UI elements use theme colors. UI Components Style guidelines