[roll] Roll fuchsia [camera][ge2d] Add const to copy assignment

llvm/llvm-project#89652 made
std::pair trivially copyable if its members are, and
it caused the following issue: "error: the parameter
for this explicitly-defaulted copy assignment operator
is const, but a member or base requires it to be
non-const". This patch adds const to copy assignment
operator to fix the issue.

Original-Bug: 354627057
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1086536
Original-Revision: a2fef69a6c032a50ac2c62ead4e7212a488ad238
GitOrigin-RevId: 18c0605dc1feadcd7020552002db782a3b26fd18
Change-Id: I74457afae466f7e65aecf1dffe938dc02ab8062b

Author: Gulfem Savrun Yeniceri

stem

@@ -11,7 +11,7 @@
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-             revision="f3fe77451f79fd41142c3e78b16a4210778be936"/>
+             revision="a2fef69a6c032a50ac2c62ead4e7212a488ad238"/>
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