Fixed plugin crash and add libraries

[abiharbani]

In a recent commit, there was a full dispose that caused the WeavePreviewComponent not being able to be reused. This causes plugin crash in the IDE when opening the Dataweave preview. The proposed solution is to recreate the WeavePreviewComponent when setting a new DWL file, because WeavePreviewComponent is always in a disposed state at this time.

In a dataweave that has java import for classes that live in a library, the Dataweave preview complains that it cannot find the class file. The proposed solution is to send all libraries, except SDK, to the agent so that the class file is available when the script engine evaluates the Dataweave in the agent.

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