[MM-53968] Includes mattermost-plugin-api into the mono repo (#24235)

Include https://github.com/mattermost/mattermost-plugin-api into the mono repo

Co-authored-by: Jesse Hallam <jesse.hallam@gmail.com>
Co-authored-by: Michael Kochell <mjkochell@gmail.com>
Co-authored-by: Alejandro García Montoro <alejandro.garciamontoro@gmail.com>
Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>
Co-authored-by: Alex Dovenmuehle <alex.dovenmuehle@mattermost.com>
Co-authored-by: Michael Kochell <6913320+mickmister@users.noreply.github.com>
Co-authored-by: Christopher Poile <cpoile@gmail.com>
Co-authored-by: İlker Göktuğ Öztürk <ilkergoktugozturk@gmail.com>
Co-authored-by: Shota Gvinepadze <wineson@gmail.com>
Co-authored-by: Ali Farooq <ali.farooq0@pm.me>
Co-authored-by: Maria A Nunez <maria.nunez@mattermost.com>
Co-authored-by: Daniel Espino García <larkox@gmail.com>
Co-authored-by: Christopher Speller <crspeller@gmail.com>
Co-authored-by: Alex Dovenmuehle <adovenmuehle@gmail.com>
Co-authored-by: Szymon Gibała <szymongib@gmail.com>
Co-authored-by: Lev <1187448+levb@users.noreply.github.com>
Co-authored-by: Jason Frerich <jason.frerich@mattermost.com>
Co-authored-by: Agniva De Sarker <agnivade@yahoo.co.in>
Co-authored-by: Artur M. Wolff <artur.m.wolff@gmail.com>
Co-authored-by: Madhav Hugar <16546715+madhavhugar@users.noreply.github.com>
Co-authored-by: Joe <security.joe@pm.me>
Co-authored-by: Ibrahim Serdar Acikgoz <serdaracikgoz86@gmail.com>
Co-authored-by: José Peso <trilopin@users.noreply.github.com>

server/public/pluginapi/cluster_test.go

@@ -0,0 +1,48 @@
+package pluginapi_test
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/mattermost/mattermost/server/public/plugin/plugintest"
+	"github.com/mattermost/mattermost/server/public/pluginapi"
+)
+
+func TestPublishPluginClusterEvent(t *testing.T) {
+	t.Run("success", func(t *testing.T) {
+		api := &plugintest.API{}
+		defer api.AssertExpectations(t)
+		client := pluginapi.NewClient(api, &plugintest.Driver{})
+
+		api.On("PublishPluginClusterEvent",
+			model.PluginClusterEvent{Id: "someID", Data: []byte("foo")},
+			model.PluginClusterEventSendOptions{SendType: model.PluginClusterEventSendTypeReliable},
+		).Return(nil)
+
+		err := client.Cluster.PublishPluginEvent(
+			model.PluginClusterEvent{Id: "someID", Data: []byte("foo")},
+			model.PluginClusterEventSendOptions{SendType: model.PluginClusterEventSendTypeReliable},
+		)
+		require.NoError(t, err)
+	})
+
+	t.Run("failure", func(t *testing.T) {
+		api := &plugintest.API{}
+		defer api.AssertExpectations(t)
+		client := pluginapi.NewClient(api, &plugintest.Driver{})
+
+		api.On("PublishPluginClusterEvent",
+			model.PluginClusterEvent{Id: "someID", Data: []byte("foo")},
+			model.PluginClusterEventSendOptions{SendType: model.PluginClusterEventSendTypeReliable},
+		).Return(errors.New("someError"))
+
+		err := client.Cluster.PublishPluginEvent(
+			model.PluginClusterEvent{Id: "someID", Data: []byte("foo")},
+			model.PluginClusterEventSendOptions{SendType: model.PluginClusterEventSendTypeReliable},
+		)
+		require.Error(t, err)
+	})
+}