fix(connector-polkadot): use dynamic import calls for ESM dependencies

[petermetz]

1. The polkadot libraries are all ESM-only so we have to import them
   in a specific way in order to avoid runtime crashes.
2. This was not done in the original implementation of the polkadot
   connector and because of that all the tests were failing.
3. Refactoring the code so that all polkadot related dependencies are
   imported dynamically fixes the issue.
4. Also fixed the issue where the getRawTransaction HTTP REST handler
   was not await ing for the result of the connector's method which broke
   the run-transaction test case (now also fixed)

Fixes #3077

Signed-off-by: Peter Somogyvari peter.somogyvari@accenture.com

Pull Request Requirements

• Rebased onto upstream/main branch and squashed into single commit to help maintainers review it more efficient and to avoid spaghetti git commit graphs that obfuscate which commit did exactly what change, when and, why.
• Have git sign off at the end of commit message to avoid being marked red. You can add -s flag when using git commit command. You may refer to this link for more information.
• Follow the Commit Linting specification. You may refer to this link for more information.

Character Limit

• Pull Request Title and Commit Subject must not exceed 72 characters (including spaces and special characters).
• Commit Message per line must not exceed 80 characters (including spaces and special characters).

A Must Read for Beginners
For rebasing and squashing, here's a must read guide for beginners.

[jagpreetsinghsasan]

LGTM, (lint ,custom checks script and polkadot tests are failing though)

[petermetz]

LGTM, (lint ,custom checks script and polkadot tests are failing though)

@jagpreetsinghsasan Oops, sorry and thanks for noticing that! I fixed the issues now (fingers crossed)