[python] Fixed the code to call the correct method to prevent duplication of Prefix added to the model when using --model-name-prefix

[Am-an-R]

Fix for the duplicate prefix / suffix addition to model names as mentioned in issue #22146. The bug causing the additional prefix was also what was causing the model not being imported like in the example provided in the issue. Building the code and generating the code will now yield the correct model names being generated as well as them being imported correctly. Fixes #22146 @cbornet, @tomplus, @krjakbrjak, @fa0311, @multani.

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[wing328]

tested locally to confirm the fix

let's give it a try

thanks for the PR