Pubmatic Adapter dont modify shared bid data

[ReinoutStevens]

Type of change

• Bugfix
• Feature
• New bidder adapter
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Does this change affect user-facing APIs or examples documented on http://prebid.org?
• Other

Description of change

Ensure pubmatic adapter does not modify a shared sizes variable

Other information

#3111

[ReinoutStevens]

Note that this still leaves a suspicious looking line https://github.com/prebid/Prebid.js/blob/master/modules/pubmaticBidAdapter.js#L120

[mkendall07]

@ReinoutStevens
Is this causing an issue somewhere?

[ReinoutStevens]

@mkendall07 The reported issue associated with this PR has been causing some problems. Atm we have reverted our code and no longer make use of Pubmatic's multi-size support, and specify multiple bids per size again (as it used to be the case).

[mkendall07]

@ReinoutStevens
ah sorry I missed the linked issue. I think Prebid team should fix this at the core level. Will look into solution as well.

[ReinoutStevens]

@mkendall07 no worries, thanks for taking a look at this.
I agree that an adapter modifying some passed objects should have no influence. I would expect a copy to be passed to each adapter, and not a shared object.
This PR is only a quick fix for a bigger problem, and I'm not sure of the impact of this change on pubmatic's adapter.

[jsnellbaker]

Closing this PR in favor of the fix put together by the Pubmatic team. #3122