Remove duplication of Uniswap e2e example

[spalladino]

The code for the uniswap trade e2e example is replicated three times in our codebase:

• As an end-to-end test
• In the canary test
• In the sandbox examples

We should have a single copy of it, and either import or symlink it where needed. Otherwise, every change to that test needs to be done on 3 exact copies of the same code.

[rahul-kothari]

I am deleting sandbox-example

What is the best course of action for merging the canary with end-to-end?

[ludamad]

We should probably have the entire end-to-end suite testable in a canary-like fashion against the sandbox and NPM packages?

[spypsy]

Closing this as duplicate of #2303

[spalladino]

Gotta love the irony of closing an issue about duplicate code as a duplicate