Add note on Bicep compiler installation

[bugle-rock]

Added note about Bicep compiler installation before running the command.

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Issue reference

[Reshrahim]

@bugle-rock - Thank you for trying the quickstart. I believe Step 1 (“Install the radCLI”) already installs the Bicep compiler. Also it might be better to not add additional commands to the quickstart unless they’re required for the getting started experience.