feat: Add options to filter conversation history messages used in sequential LLM and Agent nodes (#3653)

* feat: Add option to disable conversation history

- Add new `disableConversationHistory` boolean parameter in LLMNodes.ts and Agent.ts to optionally skip including conversation history in prompts
- Fix potential error in Agent.ts when messages array is empty by adding null safety checks
- Improve memory efficiency by allowing stateless interactions when history isn't needed

* feat: add conversation history filtering options

Replace the disable conversation history feature with a more flexible filtering system that allows selecting:
- User question only
- Last message only
- All messages (default)
- No messages

This provides more granular control over conversation context management.

* chore: break lines

* chore: removed ending semi columns

* chore: fix eslint errors

* fix(sequentialagents): improve conversation history filtering logic

- Remove unnecessary state.messages check for user_question case
- Add proper null handling for last_message and all_messages cases
- Remove @ts-ignore comments with proper typing

* Update LLMNode.ts

* Update Agent.ts

---------

Co-authored-by: Henry Heng <henryheng@flowiseai.com>

packages/components/nodes/sequentialagents/commonUtils.ts

@@ -9,7 +9,14 @@ import { Runnable, RunnableConfig, mergeConfigs } from '@langchain/core/runnable
 import { AIMessage, BaseMessage, HumanMessage, MessageContentImageUrl, ToolMessage } from '@langchain/core/messages'
 import { BaseChatModel } from '@langchain/core/language_models/chat_models'
 import { addImagesToMessages, llmSupportsVision } from '../../src/multiModalUtils'
-import { ICommonObject, IDatabaseEntity, INodeData, ISeqAgentsState, IVisionChatModal } from '../../src/Interface'
+import {
+    ICommonObject,
+    IDatabaseEntity,
+    INodeData,
+    ISeqAgentsState,
+    IVisionChatModal,
+    ConversationHistorySelection
+} from '../../src/Interface'
 import { availableDependencies, defaultAllowBuiltInDep, getVars, prepareSandboxVars } from '../../src/utils'
 import { ChatPromptTemplate, BaseMessagePromptTemplateLike } from '@langchain/core/prompts'
 
@@ -208,6 +215,34 @@ export const convertStructuredSchemaToZod = (schema: string | object): ICommonOb
     }
 }
 
+/**
+ * Filter the conversation history based on the selected option.
+ *
+ * @param historySelection - The selected history option.
+ * @param input - The user input.
+ * @param state - The current state of the sequential llm or agent node.
+ */
+export function filterConversationHistory(
+    historySelection: ConversationHistorySelection,
+    input: string,
+    state: ISeqAgentsState
+): BaseMessage[] {
+    switch (historySelection) {
+        case 'user_question':
+            return [new HumanMessage(input)]
+        case 'last_message':
+            // @ts-ignore
+            return state.messages?.length ? [state.messages[state.messages.length - 1] as BaseMessage] : []
+        case 'empty':
+            return []
+        case 'all_messages':
+            // @ts-ignore
+            return (state.messages as BaseMessage[]) ?? []
+        default:
+            throw new Error(`Unhandled conversationHistorySelection: ${historySelection}`)
+    }
+}
+
 export const restructureMessages = (llm: BaseChatModel, state: ISeqAgentsState) => {
     const messages: BaseMessage[] = []
     for (const message of state.messages as unknown as BaseMessage[]) {