remove excessive check

Author: sadym-chromium

index.bs

@@ -6368,11 +6368,7 @@ The [=remote end steps=] given |session| and |command parameters| are:
    and |command parameters| [=map/contains=] "<code>contexts</code>",
    return [=error=] with [=error code=] [=invalid argument=].
 
-1. Let |emulated user agent| be null.
-
-1. If |command parameters| [=map/contains=] "<code>userAgent</code>":
-
-   1. Set |emulated user agent| to |command parameters|["<code>userAgent</code>"].
+1. Let |emulated user agent| be |command parameters|["<code>userAgent</code>"].
 
 1. If |command parameters| [=map/contains=] "<code>contexts</code>":
 
@@ -6484,12 +6480,7 @@ The [=remote end steps=] with |command parameters| are:
    and |command parameters| doesn't [=map/contain=] "<code>contexts</code>",
    return [=error=] with [=error code=] [=invalid argument=].
 
-1. Let |emulated scripting enabled status| be null.
-
-1. If |command parameters| [=map/contains=] "<code>enabled</code>":
-
-   1. Set |emulated scripting enabled status| to
-      |command parameters|["<code>enabled</code>"].
+1. Let |emulated scripting enabled status| be |command parameters|["<code>enabled</code>"].
 
 1. If the <code>contexts</code> field of |command parameters| is present:
 
@@ -6593,15 +6584,11 @@ The [=remote end steps=] with |command parameters| are:
    and |command parameters| doesn't [=map/contain=] "<code>contexts</code>",
    return [=error=] with [=error code=] [=invalid argument=].
 
-1. Let |emulated timezone| be null.
-
-1. If |command parameters| [=map/contains=] "<code>timezone</code>":
-
-   1. Set |emulated timezone| to |command parameters|["<code>timezone</code>"].
+1. Let |emulated timezone| be |command parameters|["<code>timezone</code>"].
 
-   1. If [=IsTimeZoneOffsetString=](|emulated timezone|) returns false and
-      [=AvailableNamedTimeZoneIdentifiers=] does not [=list/contain=]
-      |emulated timezone|, return [=error=] with [=error code=] [=invalid argument=].
+1. If [=IsTimeZoneOffsetString=](|emulated timezone|) returns false and
+   [=AvailableNamedTimeZoneIdentifiers=] does not [=list/contain=]
+   |emulated timezone|, return [=error=] with [=error code=] [=invalid argument=].
 
 1. Let |navigables| be a [=/set=].