Extract the SidebarBot ClickAction to RelaxedClickAction for reuse

The ClickAction is needed to click on search chips as well. So move it
somewhere that can be reused instead of a static element on the
SidebarBot.

Bug: 405288522
Test: atest com.android.documentsui.SidebarUiTest
Flag: com.android.documentsui.flags.use_material3
Change-Id: I8b004c3cfa8f2d7075a1038106867b76ec216ea4