fix proxy call content-length header for encoded characters in payload

[christianvogt]

Closes: #1968

Description

The backend passthrough proxy used string length for the content-length header which does not match the byte length of a payload which contains encoded characters. Therefore the payload was cut short when received by the api server resulting in malformed JSON being received.

How Has This Been Tested?

Any request that uses our pass through proxy can be used for testing.
Easiest to test with projects.
Create a new project named testł.
Expect the project to be created successfully.

Test Impact

No backend tests.

Request review criteria:

Self checklist (all need to be checked):

• The developer has manually tested the changes and verified that the changes work
• Commits have been squashed into descriptive, self-contained units of work (e.g. 'WIP' and 'Implements feedback' style messages have been removed)
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has added tests or explained why testing cannot be added (unit tests & storybook for related changes)

If you have UI changes:

• Included any necessary screenshots or gifs if it was a UI change.
• Included tags to the UX team if it was a UI/UX change (find relevant UX in the SMEs section).

After the PR is posted & before it merges:

• The developer has tested their solution on a cluster by using the image produced by the PR to main

[andrewballantyne]

Hah, elegant... this is why I don't do backend development 🙂

[andrewballantyne]

Brave new world of emojis...

[openshift-ci]

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