Update New-AzStorageAccount.md (#25493)

Typo on "Immutability"

Author: PaoloFrigo

src/Storage/Storage.Management/help/New-AzStorageAccount.md

@@ -319,7 +319,7 @@ Disabled
 
 The command creates account with disable PublicNetworkAccess of the account.
 
-### Example 15: Create account with account level  mmutability policy
+### Example 15: Create account with account level Immutability policy
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