Update deprecated theme values

[erdemyerebasmaz]

• Updated and utilize AppBarTheme,
  • Updated textTheme to titleTextStyle & toolbarTextStyle,
  • Use elevation, iconTheme, backgroundColor from AppBarTheme,
• Replaced BreezDatePicker with DatePicker,
  • Filter only applies if filter has changed,
• Removed buttonColor references,
• Updated primary attribute of buttons to background & foreground color,
• Removed unused InvoiceBottomSheet and it's assets,