feat: add view fn to query operator sets for an avs

[gap-editor]

#1161

Motivation:

The mapping _operatorSets in AllocationManagerStorage.sol needs to be accessible to check if an operator is registered for a particular AVS. Currently, there is no direct way to access all operator sets for a given AVS, which makes it difficult to verify operator registration status.

Modifications:

1. Added new view function getAVSOperatorSets(address avs) to IAllocationManager interface
2. Implemented the function in AllocationManager contract
3. Function returns an array of operator set IDs for a given AVS address
4. Added NatSpec documentation for the new function

Result:

After this change:

• External contracts and users can query all operator sets for any AVS address
• Makes it easier to verify operator registration status for a particular AVS
• Improves contract interoperability and transparency
• Maintains consistent code style with existing view functions
• No security implications as this is a read-only function accessing existing public state

[gap-editor]

Hi, @0xClandestine ! Is here something wrong? Do i need something to improve?

[ypatil12]

This needs additional tests cc @bowenli86 to get this to the finish line along with @gap-editor