Enable nxapi nxos_banner test (#35033)

Signed-off-by: Trishna Guha <trishnaguha17@gmail.com>

test/integration/targets/nxos_banner/tests/cli/basic-exec.yaml

@@ -0,0 +1,41 @@
+---
+- debug: msg="START cli/nxos_banner exec test"
+
+- block:
+    - name: setup - remove exec
+      nxos_banner: &remove
+        banner: exec
+        state: absent
+        provider: "{{ cli }}"
+
+    - name: Set exec
+      nxos_banner: &exec
+        banner: exec
+        text: |
+          this is my exec banner
+          that has a multiline
+          string
+        state: present
+        provider: "{{ cli }}"
+      register: result
+
+    - assert:
+        that:
+          - "result.changed == true"
+          - "'banner exec @\nthis is my exec banner\nthat has a multiline\nstring\n@' in result.commands"
+
+    - name: Set exec again (idempotent)
+      nxos_banner: *exec
+      register: result
+
+    - assert:
+        that:
+          - "result.changed == false"
+          - "result.commands | length == 0"
+
+    - name: teardown - remove exec
+      nxos_banner: *remove
+
+  when: platform is match("N7K")
+
+- debug: msg="END cli/nxos_banner exec test"