Add selected field count to new streams table

[josephkmh]

The number of selected fields in each stream should be displayed in a new column on the streams table:

Figma designs :https://www.figma.com/proto/liLQhcbpVHiEDW18kiXQe3/01_03_CONNECTIONS?node-id=972%3A36212&scaling=min-zoom&page-id=972%3A36208&starting-point-node-id=972%3A36212&show-proto-sidebar=1

The rest of the selection UI is being added in this PR: #21058

[edmundito]

@dizel852 assigned this to you. You can work with @josephkmh to understand how column counts work. There is already some placeholder code in the table that can be uncommented as a starting point.

[dizel852]

@Upmitt
❓ A few questions:

1. Is it a Pill button component? I see the same style as the Sync Mode dropdown has

2. Does the counter should have the same styles as Sync Mode dropdown has for cases - changed(light blue background), removed(light blue background)

4. If all fields are selected, do we need to show a counter like "10/10"?

[dizel852]

Seems like I've found the answers 😅