Fix WooGraphQL Product Type Expectations

[robbiebel]

What

Fixes the error on GraphQL IDE which cause by WooGraphQL v0.21.1

Why

The GraphQL IDE becomes useless with this errors.

How

RankMathProductObjectSeo type for all WooGraphQL Product types which are in error message has been set.

Testing Instructions

Additional Info

{
  "errors": [
    "Interface field Product.seo expects type RankMathProductObjectSeo but ProductVariation.seo is type RankMathProductVariationObjectSeo.",
    "Interface field Product.seo expects type RankMathProductObjectSeo but ProductUnion.seo is type RankMathSeo.",
    "Interface field ContentNode.seo expects type RankMathContentNodeSeo but ProductUnion.seo is type RankMathSeo.",
    "Interface field Product.seo expects type RankMathProductObjectSeo but ProductWithPricing.seo is type RankMathSeo.",
    "Interface field ContentNode.seo expects type RankMathContentNodeSeo but ProductWithPricing.seo is type RankMathSeo.",
    "Interface field Product.seo expects type RankMathProductObjectSeo but ProductWithDimensions.seo is type RankMathSeo.",
    "Interface field ContentNode.seo expects type RankMathContentNodeSeo but ProductWithDimensions.seo is type RankMathSeo.",
    "Interface field Product.seo expects type RankMathProductObjectSeo but InventoriedProduct.seo is type RankMathSeo.",
    "Interface field ContentNode.seo expects type RankMathContentNodeSeo but InventoriedProduct.seo is type RankMathSeo.",
    "Interface field Product.seo expects type RankMathProductObjectSeo but DownloadableProduct.seo is type RankMathSeo.",
    "Interface field ContentNode.seo expects type RankMathContentNodeSeo but DownloadableProduct.seo is type RankMathSeo.",
    "Interface field Product.seo expects type RankMathProductObjectSeo but ProductWithAttributes.seo is type RankMathSeo.",
    "Interface field ContentNode.seo expects type RankMathContentNodeSeo but ProductWithAttributes.seo is type RankMathSeo.",
    "Interface field Product.seo expects type RankMathProductObjectSeo but ProductWithVariations.seo is type RankMathSeo.",
    "Interface field ContentNode.seo expects type RankMathContentNodeSeo but ProductWithVariations.seo is type RankMathSeo.",
    "Interface field Product.seo expects type RankMathProductObjectSeo but SimpleProductVariation.seo is type RankMathProductVariationObjectSeo."
  ]
}

Checklist:

• My code is tested to the best of my abilities.
• My code follows the WordPress Coding Standards.
• My code has proper inline documentation.
• [] I have added unit tests to verify the code works as intended.
• [] The changes in this PR have been noted in CHANGELOG.md