[Platform] [Infineon] KVS not clean config value for CYW30739

[AlvinHsiao]

Reproduction steps

1. Delete a zero-size value.

Platform

other

Platform Version(s)

No response

Type

Manually tested with SDK

(Optional) If manually tested please explain why this is only manually tested

No response

Anything else?

No response

[AlvinHsiao]

The subject of this PR contains misleading descriptions. It's a general KVS implementation fix.
When writing a zero-size value, CYW30739 only writes the key of the value to the flash because the lower layer APIs of CYW30739 doesn't support writing a zero-size value.

CHIP_ERROR KeyValueStoreManagerImpl::_Put(const char * key, const void * value, size_t value_size)
{
...
if (value_size != 0)
{
SuccessOrExit(err = CYW30739Config::WriteConfigValueBin(entry->GetValueConfigKey(), value, value_size));
}
...
}
CYW30739 only has to erase the key of a zero-size value from the flash rather than erase both the key and the value from the flash.
When the original codes tried to delete a non-existed value from the flash, the lower layer API would return an error and bypass the following codes. This is the bug we are trying to fix.