Pagination discrepancy for MemorySessionManager ---> search_long_term_memories and list_long_term_memory_records

**Describe the bug**
MemorySessionManager has 2 memory listing methods named search_long_term_memories and list_long_term_memory_records

as per boto3 docs both the methods should support pagination with nextToken

i can see list_long_term_memory_records has some pagination inside it and fetches all the records in loop where as search_long_term_memories doesnt have one

both methods pagination logic should be similar as per boto3 actual methods? if yes, search_long_term_memories also needs same looping logic and fetching all records

Also as list_long_term_memory_records brings up all the records in a loop and then do the slicing as per max_results,

- what if the records are huge in number?
- Is sequential pagination will be available in future? as even if i increase max_results value to a bigger number, i will get the values from the beginning till max_result always

**Screenshots**

boto3 links:
https://docs.aws.amazon.com/boto3/latest/reference/services/bedrock-agentcore/client/retrieve_memory_records.html
https://docs.aws.amazon.com/boto3/latest/reference/services/bedrock-agentcore/client/list_memory_records.html

MemorySessionManager.search_long_term_memories と list_long_term_memory_records から始め、nextToken の処理を、リンク先の boto3 の retrieve_memory_records および list_memory_records のドキュメントと比較します。想定されるページネーションと max_results の動作を確認します。両方のメソッドが、曖昧な取得セマンティクスのない、一貫したドキュメント化された結果を返せば完了です。

索引モデルが issue の本文から書いたものです。