Bug: Connector tool usability issues

[fatflyingpigs]

Issue:

1. Panning in connector tool is not possible (which makes it feel clunky). Imo, the connect tool should not start/end with middle+click, alt+click, or ctrl+click. This will allow the pan modes of alt/ctrl+click (which are enabled by default) to move the canvas while the connector tool is in use.
2. Switching tools (via click or hotkey) when the connector tool is in use with the "start" of the connection made will terminate the connection as though it was properly complete. I believe this behaviour is intended to either cancel or fast-swap to another tool.

Solution/Result:

• Make middle+click, alt+click, or ctrl+click not affect the connector tool.
  • Make the above click types pan, but not fully switch to the select tool or pan tool
• Switching tools should cancel the connection Feature: 'Esc' key functionality #154
  • 'Esc' should cancel the connection Feature: 'Esc' key functionality #154

Additional context:
Unrelate to this issue, @stan-smith I've tested all the older issues I've opened. They all work, good job :)

[stan-smith]

@fatflyingpigs completely agree with all of this ❤️
Also thank you for the issues, they are genuinely a joy to work on because of the detail.