fix(mise/tools): switch kubectx back to asdf plugin

The UBI method excludes supporting files like shell completions and
more.

config/mise/config.toml

@@ -60,7 +60,6 @@ show_tools = false
 "npm:yaml-language-server" = "latest"
 "ubi:BurntSushi/ripgrep" = { version = "latest", exe = "rg" }     # ripgrep
 "ubi:DarthSim/hivemind" = "latest"                                # hivemind
-"ubi:ahmetb/kubectx" = "latest"                                   # kubectx
 "ubi:ajeetdsouza/zoxide" = "latest"                               # zoxide
 "ubi:argoproj/argo-cd" = { version = "latest", exe = "argocd" }   # Argo CD
 "ubi:bcicen/ctop" = "latest"                                      # ctop
@@ -105,6 +104,7 @@ go = "latest"
 helm = "latest"
 jq = "latest"
 kubectl = "latest"
+kubectx = "latest"
 lua = "latest"
 node = "lts"
 python = "latest"