Use common.ps1 in New-TestResources to detect the language.

https://github.com/Azure/azure-sdk-tools/pull/1077#discussion_r501904126

@chidozieononiwu is working on some common scripts one of which would give you the language. If you import common.ps1 it will import the language-settings.ps1 which will have $language defined.

Start with New-TestResources and inspect how it currently detects the language. Read common.ps1 and language-settings.ps1 to understand the shared import and the defined $language value. Done means New-TestResources uses the common script for language detection and the existing related tests or workflow still pass.

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