Signed-off-by: Raphael Defosseux <raphael.defosseux@openairinterface.org>

call_process_id is a byte_string_t, but prior to this commit, we
allocate data->len_cpid, which is likely not the right size; instead,
use the sizeof operator to calculate the right size.

This prevents one of these warnings, depending on compiler (version):

  /home/richie/flexric/src/agent/e2_agent.c: In function ‘generate_aindication’:
  /home/richie/flexric/src/agent/e2_agent.c:56:25: warning: allocation of insufficient size ‘8’ for type ‘byte_array_t’ with size ‘16’ [-Walloc-size]
     56 |     ind.call_process_id = malloc(sizeof(data->len_cpid) );
        |                         ^

  /oai-ran/openair2/E2AP/flexric/src/agent/e2_agent.c:58:30: error: array subscript 'byte_array_t[0]' is partly outside array bounds of 'unsigned char[8]' [-Werror=array-bounds]
    59  |     ind.call_process_id->buf = data->call_process_id;
        |     ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
  /oai-ran/openair2/E2AP/flexric/src/agent/e2_agent.c:56:27: note: object of size 8 allocated by 'malloc'

gcc-14 warns when using FORTIFY_SOURCE in debug builds:

  /usr/include/features.h:414:4: warning: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Wcpp]
  414 | #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
      |    ^~~~~~~

Use it in release builds instead.

Fix warnings that appear when compiling dev branch with gcc-14 in debug mode

See merge request !49