disable restapi for leafRouter in slim image (sonic-net#17713)

Why I did it
For some devices with small memory, after upgrading to the latest image, the available memory is not enough.

Work item tracking
Microsoft ADO (number only):
26324242
How I did it
Disable restapi feature for LeafRouter which with slim image.

How to verify it
verified on 7050qx T1 (slim image), restapi disabled
verified on 7050qx T0 (slim image), restapi enabled
verified on 7260 T1 (normal image), restapi enabled

files/build_templates/init_cfg.json.j2

@@ -50,7 +50,11 @@
 {%- if include_mux == "y" %}{% do features.append(("mux", "{% if 'subtype' in DEVICE_METADATA['localhost'] and DEVICE_METADATA['localhost']['subtype'] == 'DualToR' %}enabled{% else %}always_disabled{% endif %}", false, "enabled")) %}{% endif %}
 {%- if include_nat == "y" %}{% do features.append(("nat", "disabled", false, "enabled")) %}{% endif %}
 {%- if include_p4rt == "y" %}{% do features.append(("p4rt", "disabled", false, "enabled")) %}{% endif %}
-{%- if include_restapi == "y" %}{% do features.append(("restapi", "enabled", false, "enabled")) %}{% endif %}
+{%- if include_restapi == "y" and BUILD_REDUCE_IMAGE_SIZE == "y" and sonic_asic_platform == "broadcom" %}
+    {% do features.append(("restapi", "{% if (DEVICE_METADATA is defined and DEVICE_METADATA['localhost'] is defined and DEVICE_METADATA['localhost']['type'] is defined and DEVICE_METADATA['localhost']['type'] is not in ['LeafRouter', 'BackEndLeafRouter']) %}enabled{% else %}disabled{% endif %}", false, "enabled")) %}
+{%- elif include_restapi == "y" %}
+    {% do features.append(("restapi", "enabled", false, "enabled")) %}
+{%- endif %}
 {%- if include_sflow == "y" %}{% do features.append(("sflow", "disabled", true, "enabled")) %}{% endif %}
 {%- if include_macsec == "y" %}{% do features.append(("macsec", "{% if 'type' in DEVICE_METADATA['localhost'] and DEVICE_METADATA['localhost']['type'] == 'SpineRouter' and DEVICE_RUNTIME_METADATA['MACSEC_SUPPORTED'] %}enabled{% else %}disabled{% endif %}", false, "enabled")) %}{% endif %}
 {%- if include_system_telemetry == "y" %}{% do features.append(("telemetry", "enabled", true, "enabled")) %}{% endif %}