Static providers property improved

[nivida]

Description

Fixes the static providers property on the AbstractWeb3Module.

Type of change

• Bug fix

Checklist:

• I have selected the correct base branch.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no warnings.
• I have updated or added types for all modules I've changed
• Any dependent changes have been merged and published in downstream modules.
• I ran npm run test in the root folder with success and extended the tests if necessary.
• I ran npm run build in the root folder and tested it in the browser and with node.
• I ran npm run dtslint in the root folder and tested that all my types are correct
• I have tested my code on the live network.

[coveralls]

Coverage increased (+0.3%) to 92.957% when pulling 19a8af4 on fix/abstract-web3-module-providers into 599c52e on 1.0.