fix(PageLayout): add maxWidth to container (#2502)

* fix(PageLayout): add maxWidth to container

* chore: add changeset

* test: update snapshots

Author: joshblack

.changeset/angry-wombats-burn.md

@@ -0,0 +1,5 @@
+---
+'@primer/react': patch
+---
+
+Add maxWidth to container of PageLayout.{Pane, Content}

src/PageLayout/PageLayout.tsx

@@ -98,7 +98,7 @@ const Root: React.FC<React.PropsWithChildren<PageLayoutProps>> = ({
               return (
                 <>
                   {slots.Header}
-                  <Box sx={{display: 'flex', flex: '1 1 100%', flexWrap: 'wrap'}}>{children}</Box>
+                  <Box sx={{display: 'flex', flex: '1 1 100%', flexWrap: 'wrap', maxWidth: '100%'}}>{children}</Box>
                   {slots.Footer}
                 </>
               )

src/PageLayout/__snapshots__/PageLayout.test.tsx.snap

@@ -25,6 +25,7 @@ exports[`PageLayout renders condensed layout 1`] = `
   -webkit-flex-wrap: wrap;
   -ms-flex-wrap: wrap;
   flex-wrap: wrap;
+  max-width: 100%;
 }
 
 .c6 {
@@ -265,6 +266,7 @@ exports[`PageLayout renders default layout 1`] = `
   -webkit-flex-wrap: wrap;
   -ms-flex-wrap: wrap;
   flex-wrap: wrap;
+  max-width: 100%;
 }
 
 .c6 {
@@ -547,6 +549,7 @@ exports[`PageLayout renders pane in different position when narrow 1`] = `
   -webkit-flex-wrap: wrap;
   -ms-flex-wrap: wrap;
   flex-wrap: wrap;
+  max-width: 100%;
 }
 
 .c6 {
@@ -829,6 +832,7 @@ exports[`PageLayout renders with dividers 1`] = `
   -webkit-flex-wrap: wrap;
   -ms-flex-wrap: wrap;
   flex-wrap: wrap;
+  max-width: 100%;
 }
 
 .c6 {

src/SplitPageLayout/__snapshots__/SplitPageLayout.test.tsx.snap

@@ -29,6 +29,7 @@ exports[`SplitPageLayout renders default layout 1`] = `
   -webkit-flex-wrap: wrap;
   -ms-flex-wrap: wrap;
   flex-wrap: wrap;
+  max-width: 100%;
 }
 
 .c6 {