Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/e73618ed93c6
Author: Evan Tseng <itoyxd@gmail.com>
Desc: Merge pull request #30605 from mozilla-b2g/revert-30120-bug-1166172

Revert "Bug 1166172 - Send MozContentEvent to gecko after the system-…

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https://hg.mozilla.org/integration/gaia-central/rev/cd4dd12e445b
Author: Evan Tseng <itoyxd@gmail.com>
Desc: Revert "Bug 1166172 - Send MozContentEvent to gecko after the system-first-paint event is received"

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https://hg.mozilla.org/integration/gaia-central/rev/0b1b68e9d0c9
Author: Evan Tseng <itoyxd@gmail.com>
Desc: Merge pull request #30120 from evanxd/bug-1166172

Bug 1166172 - Send MozContentEvent to gecko after the system-first-paint event is received r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/40bf08cb2e48
Author: Evan Xd <itoyxd@gmail.com>
Desc: Bug 1166172 - Send MozContentEvent to gecko after the system-first-paint event is received

b2g/config/gaia.json

@@ -1,9 +1,9 @@
 {
     "git": {
-        "git_revision": "4dfe2da502e4370c9670d5bc13a73d22fb37a785", 
+        "git_revision": "c553faba800955b3783c6ed5f7e049993e710ba0", 
         "remote": "https://git.mozilla.org/releases/gaia.git", 
         "branch": ""
     }, 
-    "revision": "98abafc109ce5e65f57b8dcda1e2867d2662679b", 
+    "revision": "e73618ed93c6b2571a80f4a5c699948b48300ad0", 
     "repo_path": "integration/gaia-central"
 }