Fix panic endpoints

[arnoldyahad]

due to this error:

panic: runtime error: index out of range [0] with length 0

goroutine 1 [running]:
main.getBrokers({0x974bb0, 0xc000007dc0}, {0x0, 0xc000186900, 0xc00011a7e0, 0xc000531e80, 0xc000531e70, 0xc00040eb10, 0xc00011a860, 0xc000036020, ...})
/src/main.go:145 +0x369
main.buildClusterDetails({0x974bb0?, 0xc000007dc0?}, {0x0, 0xc000186900, 0xc00011a7e0, 0xc000531e80, 0xc000531e70, 0xc00040eb10, 0xc00011a860, 0xc000036020, ...})
/src/main.go:158 +0x85
main.GetStaticConfigs({0x974bb0, 0xc000007dc0}, {0xc00017bab8, 0x1, 0xc0000061c0?})
/src/main.go:215 +0x288
main.fileSD.func1()
/src/main.go:231 +0x98
main.fileSD(0x0?, {{{0x0, 0x0}, 0xc0001f2f00, 0x0, 0x0, 0x15555, {0xc000037310, 0x1, 0x1}, ...}, ...})
/src/main.go:258 +0xa9
main.main()
/src/main.go:310 +0x3a5
stream closed EOF for kube-system/prometheus-server-0 (msk-discovery)