[PWGHF,Trigger] Revert to symmetric NsigmaDe cut for charm femto trigger

[fgrosa]

For some reason with an asymmetric cut (to keep everything compatible with deuteron and heavier) we select many tracks with very large NsigmaTPC(de), which increase drastically the selectivity of the charm femto triggers, see e.g.

[3721435:hf-filter]: [19:35:58][INFO] ACCEPTED pT = 0.8474335, NSIGMATPC 1203.5966 (cut -3), NSIGMAITS -3.3222082 (cut -4), NSIGMATOF -999 (cut -3)
[3721435:hf-filter]: [19:33:58][INFO] ACCEPTED pT = 0.99228996, NSIGMATPC 147.07945 (cut -3), NSIGMAITS -2.176171 (cut -4), NSIGMATOF -999 (cut -3)
[3721435:hf-filter]: [19:33:58][INFO] ACCEPTED pT = 0.81965065, NSIGMATPC 319.33163 (cut -3), NSIGMAITS -3.2618442 (cut -4), NSIGMATOF -999 (cut -3)
[3721435:hf-filter]: [19:33:58][INFO] ACCEPTED pT = 0.81965065, NSIGMATPC 319.33163 (cut -3), NSIGMAITS -3.2618442 (cut -4), NSIGMATOF -999 (cut -3)
[3721435:hf-filter]: [19:34:09][INFO] ACCEPTED pT = 1.0035484, NSIGMATPC 131.13118 (cut -3), NSIGMAITS -3.3340607 (cut -4), NSIGMATOF -999 (cut -3)
[3721435:hf-filter]: [19:35:58][INFO] ACCEPTED pT = 1.0433966, NSIGMATPC 888.9518 (cut -3), NSIGMAITS -3.6788256 (cut -4), NSIGMATOF -999 (cut -3)
[3721435:hf-filter]: [19:36:03][INFO] ACCEPTED pT = 0.8597881, NSIGMATPC 72.977325 (cut -3), NSIGMAITS -2.5652158 (cut -4), NSIGMATOF -68.59817 (cut -3)
[3721435:hf-filter]: [19:36:04][INFO] ACCEPTED pT = 0.923919, NSIGMATPC 295.51266 (cut -3), NSIGMAITS -3.1370604 (cut -4), NSIGMATOF -64.92043 (cut -3)

Since heavier nuclei are very likely unfeasible and we have no time to study this further, I revert to the symmetric cut around 0 @zhangbiao-phy

[github-actions]

O2 linter results: ❌ 127 errors, ⚠️ 0 warnings, 🔕 0 disabled

[alibuild]

Auto-approving on behalf of @fgrosa.