feat(ops/gerrit-webhook-to-irccat): notify when CLs are undrafted

- Extend the notification template to handle `wip-state-changed` events where a change is undrafted (i.e., `.Change.Wip` is false or not present).
- Add test cases for undrafting (should notify) and re-drafting (should not notify).
- Ensure correct handling of `.Changer.Username` for undraft notifications.
- Update Go module dependencies for test coverage. (`go mod tidy`)

This allows the IRC bot to notify when a change is moved out of
WIP/draft state, improving visibility for ready-for-review CLs.

Fixes #167.

Change-Id: I6a6a69642369726c3bd9f523ae025c34dba8c4aa
Reviewed-on: https://cl.snix.dev/c/snix/+/30641
Reviewed-by: Oleksandr Knyshuk <olk@disr.it>
Tested-by: besadii
Reviewed-by: Florian Klink <flokli@flokli.de>

ops/gerrit-webhook-to-irccat/go.sum

@@ -15,8 +15,6 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/samber/slog-http v1.6.0 h1:+rD5QtOWGTcFT7jq8Yf0EgGy87krv0pcgh9jtWkrqjQ=
 github.com/samber/slog-http v1.6.0/go.mod h1:PAcQQrYFo5KM7Qbk50gNNwKEAMGCyfsw6GN5dI0iv9g=
-github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
-github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 go.opentelemetry.io/otel v1.29.0 h1:PdomN/Al4q/lN6iBJEN3AwPvUiHPMlt93c8bqTG5Llw=
@@ -26,6 +24,7 @@ go.opentelemetry.io/otel/trace v1.29.0/go.mod h1:eHl3w0sp3paPkYstJOmAimxhiFXPg+M
 golang.org/x/sync v0.13.0 h1:AauUjRAJ9OSnvULf/ARrrVywoJDy0YS2AwQ98I37610=
 golang.org/x/sync v0.13.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=