[PM-19282] Update SsoUser ExternalId column size to 300 (#5750)

* [PM-19282] Update SsoUser ExternalId column size to 300

* [PM-19282] Add migration to update SsoUser ExternalId column size to 300 for MySQL, PostgreSQL, and SQLite

* [PM-19282] Update SsoUser ExternalId column size conditionally based on existing schema

* Bumped date on migration script name

util/PostgresMigrations/Migrations/20250429113739_SsoExternalId.cs

@@ -0,0 +1,43 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Bit.PostgresMigrations.Migrations;
+
+/// <inheritdoc />
+public partial class SsoExternalId : Migration
+{
+    /// <inheritdoc />
+    protected override void Up(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.AlterColumn<string>(
+            name: "ExternalId",
+            table: "SsoUser",
+            type: "character varying(300)",
+            maxLength: 300,
+            nullable: true,
+            collation: "postgresIndetermanisticCollation",
+            oldClrType: typeof(string),
+            oldType: "character varying(50)",
+            oldMaxLength: 50,
+            oldNullable: true,
+            oldCollation: "postgresIndetermanisticCollation");
+    }
+
+    /// <inheritdoc />
+    protected override void Down(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.AlterColumn<string>(
+            name: "ExternalId",
+            table: "SsoUser",
+            type: "character varying(50)",
+            maxLength: 50,
+            nullable: true,
+            collation: "postgresIndetermanisticCollation",
+            oldClrType: typeof(string),
+            oldType: "character varying(300)",
+            oldMaxLength: 300,
+            oldNullable: true,
+            oldCollation: "postgresIndetermanisticCollation");
+    }
+}

util/PostgresMigrations/Migrations/DatabaseContextModelSnapshot.cs

@@ -682,8 +682,8 @@ namespace Bit.PostgresMigrations.Migrations
                         .HasColumnType("timestamp with time zone");
 
                     b.Property<string>("ExternalId")
-                        .HasMaxLength(50)
-                        .HasColumnType("character varying(50)")
+                        .HasMaxLength(300)
+                        .HasColumnType("character varying(300)")
                         .UseCollation("postgresIndetermanisticCollation");
 
                     b.Property<Guid?>("OrganizationId")