Bluetooth: controller: split: Fix procedure complete event generation

[cvinayak]

Describe the bug
Generate PHY update complete and Conn Update events after the on-air instant

To Reproduce
Steps to reproduce the behavior:

1. mkdir build; cd build
2. cmake -DBOARD=board_xyz
3. make
4. See error

Expected behavior
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Impact
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showstopper

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Environment (please complete the following information):

• OS: (e.g. Linux, MacOS, Windows)
• Toolchain (e.g Zephyr SDK, ...)
• Commit SHA or Version used

Additional context
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[cvinayak]

Use inspiration from legacy controller: 2bf9d49

[carlescufi]

@kruithofa @cvinayak is this still an issue on the current EBQ runs?

[cvinayak]

@carlescufi This is not an issue for the runs, we have workaround. Fix be postpone as a requirement to the new LLCP work.

[cvinayak]

@carlescufi this depends on new LLCP work, not worth new effort to fix this in current split controller.