manifest: remove submodules true for hal_telink

Fixes: #52113

The PR #45903 included a `submodules: true` for the hal_telink project.

However, that project contains a submodule with binary libraries.

This is circumventing the rules regarding binary blobs in the Zephyr
project as specified here:
https://docs.zephyrproject.org/latest/contribute/bin_blobs.html
Therefore remove the submodules field.

Links to the submodule with binary blobs:
https://github.com/zephyrproject-rtos/hal_telink/tree/ \
95431ef5ec667ae5b1a0e4b59d1a5753396bd169/tlsr9/ble/proj_lib
pointing to this submodule with binary blobs:
https://github.com/telink-semi/zephyr_hal_telink_b91_ble_lib/tree/

 \
0a49c9bf3cfe4684cc27fbaa6ad070186703e452

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>