fix: onCompleted not updating regression

[mmahalwy]

Fixes regression caused by:
f1a9770#diff-fb7fa652de6d84c08b87344a06a4d120b664c6e8bf491d16575794c755141477R136-R142

I tested this on 3.4.0 and it works as expected. This broke on 3.5.x. I think it's also related to this issue but for queries.

I also wrote the tests and confirmed that tests were failing prior to my change.

Checklist:

• If this PR is a new feature, please reference an issue where a consensus about the design was reached (not necessary for small changes)
• Make sure all of the significant new logic is covered by tests

[mmahalwy]

cc @brainkim as your change caused the regression

[valentinbourqui]

We detected the same regression and without this fix we are not able to update to update Apollo and to update GraphQL with version 16. All forms are not working anymore. And I'm a little bit afraid to wait long time when I see all pull requests open. This fix must be treated with a higher priority.

[mmahalwy]

Tbh it's super disappointing this has been open for a while and no attention..

[benjamn]

Thanks for diagnosing/fixing/testing this, and sorry for the wait @mmahalwy!

[brainkim]

@mmahalwy Thanks for this!

[mmahalwy]

Np! Thanks @brainkim and @benjamn for making this great library!

[dankolesnikov]

@mmahalwy oh my, great find - THANK YOU!

[nathanredblur]

Thank you for this fix.

I think this error was also affecting useLazyQuery
I had 3.5.5 and when I had this.

const onCompleted = () => console.log("Success")

const [fetchCategory, data, error }] =
    useLazyQuery(PAYMENT_METHOD_FORM_CATEGORY_QUERY, {
      fetchPolicy: 'cache-first',
      onCompleted: onCompleted,
    });

on call fetchCategory the first time, I get the console.log
but on call the second time, I did'n had the log.

on move on to the version 3.5.8, this error it's gone.
but maybe a test will be good to ensure this error not happen again.