Ability to tell about any dynamic import specifiers deno_graph could not statically analyze

[dsherret]

It would be useful for deno vendor to warn when there's a dynamic import specifier that deno_graph can't statically analyze.

For example, given the following:

const value = (() => "./logger.ts")();
const { Logger } = await import(value);

This might be and is at the current moment a dynamic import deno_graph doesn't know how to statically analyze for. It would be useful for deno_graph to be able to say that somehow so the CLI can warn about these for deno vendor.