Enabled USBDevice in targets.json for H743ZI2

[rvasquez6089]

Summary of changes

Enabled USBDevice for H743ZI2 in the targets.json . It has been tested and merged from another pull request but I think someone forgot to add it to the targets.json file. I just Tested this change with tag mbed-os-6.6.0 on the H743ZI2 with USBSerial and it works fine for me.
This will allow all users to use USB drivers with the H743ZI2.

Impact of changes

Migration actions required

Documentation

Related to this PR.
#13780
Just added USBDevice to support this previous PR.

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Pull request type

[x] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

Tests from the previous PR might be relevant.
#13780 (comment)

[] No Tests required for this change (E.g docs only update)
[x] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

@jeromecoutant
@mbedmain

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