chore: Increase character limit for external url fields (#7230)

- Increase the external url field validation to 2048 characters

fixes: https://github.com/chatwoot/chatwoot/issues/7098

spec/models/agent_bot_spec.rb

@@ -12,4 +12,19 @@ RSpec.describe AgentBot do
     it_behaves_like 'access_tokenable'
     it_behaves_like 'avatarable'
   end
+
+  context 'when it validates outgoing_url length' do
+    let(:agent_bot) { create(:agent_bot) }
+
+    it 'valid when within limit' do
+      agent_bot.outgoing_url = 'a' * Limits::URL_LENGTH_LIMIT
+      expect(agent_bot.valid?).to be true
+    end
+
+    it 'invalid when crossed the limit' do
+      agent_bot.outgoing_url = 'a' * (Limits::URL_LENGTH_LIMIT + 1)
+      agent_bot.valid?
+      expect(agent_bot.errors[:outgoing_url]).to include("is too long (maximum is #{Limits::URL_LENGTH_LIMIT} characters)")
+    end
+  end
 end