Improve consistency of GetBlueprintPolicy requests

[ivan-p92]

Problem description

The GetBlueprintPolicyRequests are not consistent with ResourceUrn anymore.

Processing platforms:

message GetBlueprintPolicyRequest {
    string platform_id = 1 [(buf.validate.field).string = {min_len: 1}];
    entities.v1alpha.Table table = 2;
    optional string fqn = 3;
}

Data catalogs:

message GetBlueprintPolicyRequest {
  string catalog_id = 1 [(buf.validate.field).string = {min_len: 1}];
  optional string database_id = 2;
  optional string schema_id = 3;
  string table_id = 4 [(buf.validate.field).string = {min_len: 1}];
  string fqn = 5;
}

Proposed solution
Consider refactoring the requests.