Fix trafficnow filtering

[sharhio]

Proposed Changes

• When single alerts are split into mode specific cards the mode filtering was not applied correctly and unwanted mode cards were shown. Splitting now takes into account the selected filters.
• Also did some refactoring and added tests

Pull Request Check List

• A reasonable set of unit tests is included
• Console does not show new warnings/errors
• Changes are documented or they are self explanatory
• This pull request does not have any merge conflicts
• All existing tests pass in CI build

Review

• Read and verify the code changes
• Test the functionality by running the UI locally with all popular browsers available in your platform
• Check that the implementation matches the design, when such one is defined in an issue in Azure Boards
• Merge the pull request

[hjvuor]

Filtering by mode works now but if searching for a specific route or just favorite routes the duplicate cards for other modes are shown.

[hjvuor]

I think this might've been an already existing bug but the bus filter seems to leave out bus-local and bus-express entities (might probably also be bugged for speedtrams and replacement buses but couldn't verify quickly). modeUtils.js contains the getRouteMode function that has the correct mapping but it does not seem like such is used anywhere in the trafficnow page.