fix(panic): don't skip api key validation and client creation for update subcommands to avoid panics

[gustavofalco-uala]

This PR fixes a panic that is happening whenever you execute a subcommand update (e.g.: assistant update).

Example:

vapi assistant update 123 --json '{}'

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x8 pc=0x100ce8838]

goroutine 1 [running]:
github.com/VapiAI/cli/pkg/client.(*VapiClient).DoRawJSON(0x0, {0x101076800, 0x1015fbc80}, {0x100d5ef13, 0x5}, {0x14000206700, 0xf}, {0x140002066e8, 0x2, 0x8})
	/home/runner/work/cli/cli/pkg/client/client.go:84 +0x58
github.com/VapiAI/cli/cmd.init.func26(0x1015c32e0, {0x140001f30b0?, 0x0?, 0x0?})
	/home/runner/work/cli/cli/cmd/assistant.go:282 +0x25c
github.com/VapiAI/cli/cmd.init.TrackCommandWrapper.func86(0x1015c32e0, {0x140001f30b0, 0x1, 0x3})
	/home/runner/work/cli/cli/pkg/analytics/utils.go:14 +0x84
github.com/spf13/cobra.(*Command).execute(0x1015c32e0, {0x140001f3020, 0x3, 0x3})
	/home/runner/go/pkg/mod/github.com/spf13/[email protected]/command.go:1015 +0x844
github.com/spf13/cobra.(*Command).ExecuteC(0x1015c74e0)
	/home/runner/go/pkg/mod/github.com/spf13/[email protected]/command.go:1148 +0x384
github.com/spf13/cobra.(*Command).Execute(...)
	/home/runner/go/pkg/mod/github.com/spf13/[email protected]/command.go:1071
github.com/VapiAI/cli/cmd.Execute()
	/home/runner/work/cli/cli/cmd/root.go:193 +0x2c
main.main()
	/home/runner/work/cli/cli/main.go:42 +0x1f0