[FLINK-25947][build] Simplify shade-plugin configuration

[zentol]

Streamline the table-planner shade-plugin configuration to again use the default shade-flink execution, which is covered by the license checker. This is just a remnant from the development that wasn't re-visited.

I've verified that the contents of the generated jars is identical.

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CI report:

• 47f8d63 Azure: SUCCESS

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Last check on commit 47f8d63 (Fri Feb 04 08:00:49 UTC 2022)

Warnings:

• 1 pom.xml files were touched: Check for build and licensing issues.
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[slinkydeveloper]

Thank you for this @zentol!