py/map: use MP_ERROR_TEXT for mp_map_presize error message

[romanz]

Similar to other call sites of mp_raise_msg_varg:

py/runtime.c
951:    mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("need more than %d values to unpack"), (int)seq_len);
957:    mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("too many values to unpack (expected %d)"), (int)num);
1018:    mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("need more than %d values to unpack"), (int)seq_len);

Following https://github.com/trezor/trezor-firmware/pull/4961/files#r2086986643.