west: advance Zephyr pin to 2026-03-15 main

zephcore/patches/zephyr/0006-blobs-py.patch

@@ -1,5 +1,5 @@
 diff --git a/scripts/west_commands/blobs.py b/scripts/west_commands/blobs.py
-index 14f0412cda5..615ba602a6b 100644
+index 651fa0288ff..45d66593421 100644
 --- a/scripts/west_commands/blobs.py
 +++ b/scripts/west_commands/blobs.py
 @@ -288,7 +288,7 @@ class Blobs(WestCommand):

zephcore/west.yml

@@ -6,7 +6,7 @@ manifest:
   projects:
     - name: zephyr
       remote: zephyrproject-rtos
-      revision: e7c454caf8192d9063b7ce1ec8497a04d11e97de
+      revision: 17971b7bf45163e0ef202732290f20b3b46f9743
       import: true
 
   self: