fix: allow overriding default import map

[NtTestAlert]

Allow overriding defaultsByName either by explicitly setting the 0x00.. address in the import statement, by setting it to from "DYNAMIC", or by modifying the defaultsByName map (now exported)

Also including a fix for broken register-contract.cdc

---

For contributor use:

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[changeset-bot]

⚠️ No Changeset found

Latest commit: f04e609

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[NtTestAlert]

if the address is explicitly set it skips FlowManager.getAddress
(so setContractAddress behavior slightly changed - shouldn't be a problem tho)

so might want to change it to only expose defaultsByName if this is not desired