[TTS] Shorten IPH-CS availability for testconfig.

Shortens the "availability" setting for In Product Help for
Contextual Search, which will match our server-configs and seems
better than the long window currently in place.

BUG=822087

Change-Id: I583428cd101973a0c4d4e4950b014591d1006d8c
Reviewed-on: https://chromium-review.googlesource.com/981318Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: Donn Denman <donnd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546209}

testing/variations/fieldtrial_testing_config.json

@@ -127,7 +127,7 @@
                 {
                     "name": "PromotePanelOpeningExperiment",
                     "params": {
-                        "availability": ">=30",
+                        "availability": ">=14",
                         "event_1": "name:contextual_search_promote_panel_open_iph_trigger;comparator:<2;window:680;storage:680",
                         "event_2": "name:contextual_search_panel_opened;comparator:<3;window:90;storage:90",
                         "event_trigger": "name:contextual_search_promote_panel_open_iph_trigger;comparator:==0;window:90;storage:680",
@@ -150,7 +150,7 @@
                 {
                     "name": "PromoteTapExperiment",
                     "params": {
-                        "availability": ">=30",
+                        "availability": ">=14",
                         "event_1": "name:contextual_search_panel_opened;comparator:>=2;window:90;storage:90",
                         "event_2": "name:contextual_search_promote_tap_iph_trigger;comparator:<2;window:680;storage:680",
                         "event_trigger": "name:contextual_search_promote_tap_iph_trigger;comparator:==0;window:90;storage:680",
@@ -173,7 +173,7 @@
                 {
                     "name": "WebSearchExperiment",
                     "params": {
-                        "availability": ">=30",
+                        "availability": ">=14",
                         "event_1": "name:web_search_performed;comparator:>=1;window:90;storage:90",
                         "event_2": "name:contextual_search_web_search_iph_trigger;comparator:<2;window:680;storage:680",
                         "event_3": "name:contextual_search_panel_opened;comparator:>0;window:680;storage:680",