Cancelling VM press-to-release is janky after sliding finger upwards

#### Describe the bug.
When sliding finger upwards, to the side, and then down, the slider is "locked" to the vertical axis.

https://user-images.githubusercontent.com/22740616/129975150-4a5ef9bb-ce73-49fd-8ebd-17b1c2c4d078.MOV

You can see me try to "get" it down in the slider in the end (my finger is halfway in the middle of the screen), and eventually I move my finger over the icon itself, after which is "snaps" to my finger again.

#### Step by step
1. Press on VM indicator
2. Move finger upwards, halfway until the "locking phase"
3. Move finger sideways
4. Move finger down, observe it doesn't "snap" to cancel it.

#### Expected behavior
Observe a "snap" of the VM indicator to cancel the VM

#### Contextual information:
- Device: iPhone 11
- OS: iOS 14.7
- App Version: 1.5.1

Start by reproducing the VM indicator press-to-release gesture using the issue's steps on the reported iPhone 11 and iOS 14.7 context, then trace the Swift iOS implementation of that indicator and its vertical-axis locking. Done means moving upward, sideways, and down makes the VM indicator snap back to cancel as expected.

Written by the indexing model from the issue text.