Fix token parsing from custom env variable or org token

[VictorAvelar]

Description

Fixed the mollie client initialization, conceptually the second parameter passed to the NewConfig method should be the name of the environment variable from which the token should be parsed, this behaviour was not accurate and instead, the explicit string was being added as a token.

Motivation and context

Why is this change required? What problem does it solve?

It fixed an error encountered when running the static token auth example code.

How has this been tested?

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The existing test suite is passing.

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

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