[rocketmq-connect-runtime] load class failed from classpath

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**BUG REPORT**

1. Please describe the issue you observed:
plugin path does not exist jar. classpath exist jar.load class failed

- What did you do (The steps to reproduce)?

- What did you expect to see?

- What did you see instead?

2. Please tell us about your environment:

3. Other information (e.g. detailed explanation, logs, related issues, suggestions how to fix, etc):

**FEATURE REQUEST**

1. Please describe the feature you are requesting.

2. Provide any additional detail on your proposed use case for this feature.

2. Indicate the importance of this issue to you (blocker, must-have, should-have, nice-to-have). Are you currently using any workarounds to address this issue?

4. If there are some sub-tasks using -[] for each subtask and create a corresponding issue to map to the sub task:

- [sub-task1-issue-number](example_sub_issue1_link_here): sub-task1 description here,
- [sub-task2-issue-number](example_sub_issue2_link_here): sub-task2 description here,
- ...

Start in the rocketmq-connect-runtime classpath and plugin-loading entry points, then reproduce the reported case where the plugin path lacks a JAR but the classpath contains one. Compare the expected and observed class-loading behavior and document a failing test or minimal reproduction before defining the fix.

Written by the indexing model from the issue text.