Fix: fix starknet plugin by replacing walletProvider with portfolio provider

[Jonatan-Chaverri]

Relates to

https://github.com/elizaOS/eliza/issues/2028

Risks

Low risk, just fixing something that use to be broken so that people now can begin to use the starknet plugin.

Background

What does this PR do?

Fixes the starknet plugin by updating some broken references.

What kind of change is this?

Bug fixes

Documentation changes needed?

My changes do not require a change to the project documentation.

Testing

Where should a reviewer start?

Detailed testing steps

• Clone the eliza-starter repo
• replace the starknet plugin dependency in package.json with "@elizaos/plugin-starknet": "file:./plugin-starknet", where plugin-starknet is the path to the plugin-starknet folder of the plugin that was changed here.
• cd into the plugin folder, build the plugin with pnpm build
• install the plugin in eliza-starter with pnpm i
• add the plugin in your character plugins
• run the project with pnpm start, it should include the starknet actions and run without issues.