fix: Read Point from Period and not Series elements

[MWO1024]

Description

• We accidentally read the points from the Series element, instead of the Period for JSON.
• We assumed that a Point always had all its values for JSON. This is incorrect, as two of them are nullable.
• We created a lot of points for our behaviour tests. This is now reduced to four: one for each structural case.
• We did not handle decimals correctly wrt assertion and temporary serialisation.

Observation

• GivenIncomingMessagesWithDelegationTests relies on eBix for RSM-12. It should work for XML/JSON too, but it does not. We should fix this in another PR.

References

https://app.zenhub.com/workspaces/mosaic-60a6105157304f00119be86e/issues/gh/energinet-datahub/team-mosaic/377

Checklist

• Should the change be behind a feature flag?
• Can the feature be meaningfully disabled or circumvented if there are issues (e.g., database-breaking changes)?
• Has it been considered whether data is being delivered to the wrong actor?
• Subsystem test executed (dev_002/dev_003)
• Is there time to monitor state of the release to Production?
• Reference to the task

[github-actions]

Test results for \source\Tests\bin\Release\net8.0\Energinet.DataHub.EDI.Tests.dll

1 573 tests   1 573 ✅  16s ⏱️
    1 suites      0 💤
    1 files        0 ❌

Results for commit be2ac08.

♻️ This comment has been updated with latest results.

[lasrinnil]

• Reverted 'RequestAndPeekFormatPairs' approch - while it is technically plausible for a actor to request in one format, and peek in another. It is not the inteded use, and not how the system is used by the actors.

• Observation: if all new messages we are yet to support have the same amounts of integrationtests I worry for this test approach.

  • Almost all of these tests have nothing to do with the specific messagetype under test.
  • Could we go with another approch to make sure that these tests would not have to be made for every type we support?