Missing checks of return values of settings_runtime_set()

[Hxinrong]

Hello,
As shown in the API documentation, function settings_runtime_set() is used to set a value with a specific key to a module handler, returns 0 on success, non-zero on failure. But in the following codes, the return values are not error checked.

zephyr/tests/bluetooth/ll_settings/src/main.c

Lines 39 to 47 in 0a0404d

	svn = 0x1234;
	settings_runtime_set("bt/ctlr/subver", &svn, sizeof(svn));
	zassert_equal(ll_settings_subversion_number(), svn,
	"Subversion number does not match");
	svn = 0x5678;
	settings_runtime_set("bt/ctlr/subver", &svn, sizeof(svn));
	zassert_equal(ll_settings_subversion_number(), svn,
	"Subversion number does not match");

However, in the same file, the return values of the following call sites are checked, which have the same code structure.

zephyr/tests/bluetooth/ll_settings/src/main.c

Lines 22 to 32 in 0a0404d

	cid = 0x1234;
	err = settings_runtime_set("bt/ctlr/company", &cid, sizeof(cid));
	zassert_equal(err, 0, "Setting Company Id failed");
	zassert_equal(ll_settings_company_id(), cid,
	"Company Id does not match");
	cid = 0x5678;
	err = settings_runtime_set("bt/ctlr/company", &cid, sizeof(cid));
	zassert_equal(err, 0, "Changing Company Id failed");
	zassert_equal(ll_settings_company_id(), cid,
	"Company ID does not match");