- new panel created: `SwapInputPanel`
- some cleanups to the needed stores
- created a SB page demonstrating the use of 2 panels and the
`SwapExchangeButton`
- created QML tests
Fixes#14781
1. A dropdown arrow should not be visible in the context of selecting token
2. Unnecessary padding added when expanding balances in the send modal popup
fixes #12254,#12256