adds manual gpid to prebid ad unit and launch to 99% of users

[dskamiotis]

What does this change?

The GPID is being added to enable the successful sending of GPID to prebid vendors. This implementation uses the GPT Pre-Auction module, as recommended by the Prebid Docs if your project is using GAM/GPT.

Why?

We are adding the GPID to prebid as part of the OpenRTB framework, there isa field in the impressionExtension object called imp.ext.gpid. This will allow uis to conform to the protocol by sending a standardised GPID across all SPP's.
The Guardian’s ad server (GAM) to Prebid needs to follow certain standards to ensure that Prebid can interpret the information correctly and that all exchanges involved in the auction can handle and propagate it.

This includes:

• updating the PrebidAdUnit class to include a method to dynamically generate a GPID for each ad unit

• using the Unique ad slots method outlined in the docs:

• Including the GPID to 99% of users - users in variant with shouldIncludeGpid

pbjs.addAdUnits({
    code: '/1111/homepage-leftnav',
    ortb2Imp: {
        ext: {
            gpid: "/1111/homepage-leftnav",
        data: {
                pbadslot: "/1111/homepage-leftnav"
            }
        }
    },
    mediaTypes: ...
    bids: ...
});

• Added Testing - 1% control and 1% variant
• Control - continues usuing existing protocol data structure
• Variant - adds the new structure:

ortb2Imp: {
        ext: {
            gpid: "/1111/homepage-leftnav",
        data: {
                pbadslot: "/1111/homepage-leftnav"
            }
        }

OpenRTB in professor prebid - Control - #ab-gpidPrebid=control

OpenRTB in professor prebid - Variant - #ab-gpidPrebid=variant

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🦋 Changeset detected

Latest commit: c88a7b4

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@guardian/commercial	Patch

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[github-actions]

Ad load time test results

For consented, top-above-nav took on average 5426ms to load.
For consentless, top-above-nav took on average 3012ms to load.

Test conditions:

• 5mbps download speed
• 1.5mbps upload speed
• 150ms latency