[feature] KEP-11385: Add validation for Literal runtime parameters in API Server and Driver

[mprahl]

Feature Area

/area backend

Part of KEP-11385.

Acceptance Criteria

The ComponentInputsSpec_ParameterSpec struct should be updated with a literals field:

type ComponentInputsSpec_ParameterSpec struct {
    state protoimpl.MessageState `protogen:"open.v1"`
    Type PrimitiveType_PrimitiveTypeEnum `protobuf:"varint,1,opt,name=type,proto3,enum=ml_pipelines.PrimitiveType_PrimitiveTypeEnum" json:"type,omitempty"`
    ParameterType ParameterType_ParameterTypeEnum `protobuf:"varint,2,opt,name=parameter_type,json=parameterType,proto3,enum=ml_pipelines.ParameterType_ParameterTypeEnum" json:"parameter_type,omitempty"`
    DefaultValue *structpb.Value `protobuf:"bytes,3,opt,name=default_value,json=defaultValue,proto3" json:"default_value,omitempty"`
    IsOptional bool `protobuf:"varint,4,opt,name=is_optional,json=isOptional,proto3" json:"is_optional,omitempty"`
    Description   string `protobuf:"bytes,5,opt,name=description,proto3" json:"description,omitempty"`
    Literals []*structpb.Value `protobuf:"bytes,6,rep,name=literals,proto3" json:"literals,omitempty"`
    unknownFields protoimpl.UnknownFields
    sizeCache     protoimpl.SizeCache
}

Acceptance Criteria

• ComponentInputsSpec_ParameterSpec proto contains a literals field.
• Pipeline Run Server checks each runtime parameter’s ComponentInputsSpec_ParameterSpec literals field for a non-empty value. Runtime parameter is validated against this field if non-empty. (Hint: v2_template.validatePipelineJobInputs())
• Extend backend/src/v2/driver.resolveInputParameter() to validate resolved upstream inputs against Literal parameters.
• Validate these changes by adding the valid and invalid cases outlined in the KEP to the workflow compiler unit test cases. Only include behavior outlined in the Workflow Compiler column.

[khushiiagrawal]

/assign

I'd like to work on this issue. I've understand the requirements for adding the literals field validation and will add the unit tests.