livepeer_cli error when getting stats from older version of livepeer

[eliteprox]

Describe the bug
When launching livepeer_cli version 0.5.35 with an older version of livepeer, the following error occurs while trying to get statistics (that don't exist in older version) from livepeer at runtime.

panic: interface conversion: interface {} is nil, not map[string]interface {}

goroutine 1 [running]:
main.(*wizard).getBroadcasterPrices(0xc0003a9b00)
        /home/runner/work/go-livepeer/go-livepeer/cmd/livepeer_cli/wizard_stats.go:499 +0x4c6
main.(*wizard).orchestratorStats(0xc0003a9b00)
        /home/runner/work/go-livepeer/go-livepeer/cmd/livepeer_cli/wizard_stats.go:213 +0x6b
main.(*wizard).stats(0xc0003a9b00, 0x1)
        /home/runner/work/go-livepeer/go-livepeer/cmd/livepeer_cli/wizard_stats.go:90 +0xcb5
main.(*wizard).run(0xc0003a9b00)
        /home/runner/work/go-livepeer/go-livepeer/cmd/livepeer_cli/livepeer_cli.go:157 +0x2c5
main.main.func1(0xc0002ccc60)
        /home/runner/work/go-livepeer/go-livepeer/cmd/livepeer_cli/livepeer_cli.go:57 +0x4f8
github.com/urfave/cli.HandleAction({0x2bab80, 0x43de70}, 0xc0005a6c40)
        /home/runner/go/pkg/mod/github.com/urfave/cli@v1.22.2/app.go:523 +0xa8
github.com/urfave/cli.(*App).Run(0xc0005a6c40, {0xc0000322e0, 0x1, 0x1})
        /home/runner/go/pkg/mod/github.com/urfave/cli@v1.22.2/app.go:285 +0x734
main.main()
        /home/runner/work/go-livepeer/go-livepeer/cmd/livepeer_cli/livepeer_cli.go:63 +0x34e

To Reproduce
Steps to reproduce the behavior:

1. Install Livepeer release 0.5.34 package binaries
2. Update only livepeer_cli to release 0.5.35
3. Run livepeer_cli
4. See error

Expected behavior

• livepeer_cli should launch without error, it should display Base price for broadcasters as a blank string.
• Option 20 "Set price per broadcaster" might also need to be disabled, as the feature did not exist in older version and would not work. Test for any backwards compatible issues.

Desktop (please complete the following information):

• OS: Ubuntu 22.04