Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/1017257c6c02
Author: Yura Zenevich <yura.zenevich@gmail.com>
Desc: Merge pull request #30412 from yzen/bug-1162040-system

Bug 1162040 - updating accessibility for gaia-icons used in system app.

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https://hg.mozilla.org/integration/gaia-central/rev/f7aea3a0f18f
Author: Yura Zenevich <yzenevich@mozilla.com>
Desc: Bug 1162040 - updating accessibility for gaia-icons used in system app. r=mikehenrty

b2g/config/gaia.json

@@ -1,9 +1,9 @@
 {
     "git": {
-        "git_revision": "1d62b32408567f9f7cf1c71c1e5a0c6593be757b", 
+        "git_revision": "55858863f320efc73c0bfd9b3eef905e49998e39", 
         "remote": "https://git.mozilla.org/releases/gaia.git", 
         "branch": ""
     }, 
-    "revision": "63c872ccb3541c2ddb0d67f112480eb8f2650cda", 
+    "revision": "1017257c6c025ab47d3a7448ca7aecaf5a2edc84", 
     "repo_path": "integration/gaia-central"
 }