[PM-12601] Add discount to MSP during creation in Admin Portal (#5391)

* Add Provider DiscountId to database and Stripe customer

* Fix tests

* Add missing EF migrations

* Run dotnet format

util/PostgresMigrations/Migrations/20250213140406_AddColumn_ProviderDiscountId.cs

@@ -0,0 +1,27 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Bit.PostgresMigrations.Migrations;
+
+/// <inheritdoc />
+public partial class AddColumn_ProviderDiscountId : Migration
+{
+    /// <inheritdoc />
+    protected override void Up(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.AddColumn<string>(
+            name: "DiscountId",
+            table: "Provider",
+            type: "text",
+            nullable: true);
+    }
+
+    /// <inheritdoc />
+    protected override void Down(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.DropColumn(
+            name: "DiscountId",
+            table: "Provider");
+    }
+}

util/PostgresMigrations/Migrations/DatabaseContextModelSnapshot.cs

@@ -287,6 +287,9 @@ namespace Bit.PostgresMigrations.Migrations
                     b.Property<DateTime>("CreationDate")
                         .HasColumnType("timestamp with time zone");
 
+                    b.Property<string>("DiscountId")
+                        .HasColumnType("text");
+
                     b.Property<bool>("Enabled")
                         .HasColumnType("boolean");