tctl [v16] fails if device mode "required" is set in the config file

[codingllama]

Expected behavior:

tctl works in all scenarios.

Current behavior:

tctl using the user's identity works:

$ tctl users ls
> User                          Roles                                
> ----------------------------- ------------------------------------ 
> llama                         access,editor

tctl using a config file fails:

$ TELEPORT_CONFIG_FILE=/path/to/teleport.yaml tctl users ls
> ERROR: device trust mode "required" requires Teleport Enterprise

tctl Enterprise v15, with the same invocation as above, works:

$ tctl15 version
> Teleport Enterprise v15.4.9 git:v15.4.9-0-gaea5781 go1.22.5

$ TELEPORT_CONFIG_FILE=/path/to/teleport.yaml tctl15 users ls
> User                          Roles                                
> ----------------------------- ------------------------------------ 
> alpaca                        access,editor,require-trusted-device 

A certain conjunction of factors has to be present for the failure to happen:

1. tctl is build with "OSS modules" (always true for v16+)
2. A teleport config file is used (not user identity)
3. The teleport config file is Enterprise and has device_trust.mode=required set

version: v1
teleport:
  # not relevant

auth_service:
  # not relevant, except for
  enabled: "yes"
  authentication:
    device_trust:
      mode: required

This hits the following lines, in sequence:

• teleport/tool/tctl/common/tctl.go

  Line 325 in 3c0b25a

  if err = config.ApplyFileConfig(fileConf, cfg); err != nil {

• teleport/lib/config/configuration.go

  Line 614 in 3c0b25a

  err = applyAuthConfig(fc, cfg)

• teleport/lib/config/configuration.go

  Line 949 in 3c0b25a

  if err := dtconfig.ValidateConfigAgainstModules(cfg.Auth.Preference.GetDeviceTrust()); err != nil {

• teleport/lib/devicetrust/config/config.go

  Line 54 in 3c0b25a

  return trace.BadParameter("device trust mode %q requires Teleport Enterprise", dt.Mode)

which then make the invocation fail, as the binary modules don't match the configuration.

Bug details:

• Teleport version: v16+
• Recreation steps: see above
• Debug logs: not necessary / see above

[codingllama]

All backports are out. Good to close once v16 lands.