Remove use of use_key_equivalents from linux keymap as it does nothing (#24422)

`use_key_equivalents` does nothing on linux, as key equivalents are only
supported on mac. While it could be sensible to anticipate support,
right now it is only used in these few spots, so removing it.

Release Notes:

- N/A

assets/keymaps/default-linux.json

@@ -496,7 +496,6 @@
   },
   {
     "context": "Editor && showing_completions",
-    "use_key_equivalents": true,
     "bindings": {
       "enter": "editor::ConfirmCompletion",
       "tab": "editor::ComposeCompletion"
@@ -511,7 +510,6 @@
   },
   {
     "context": "Editor && inline_completion && !inline_completion_requires_modifier",
-    "use_key_equivalents": true,
     "bindings": {
       "tab": "editor::AcceptInlineCompletion"
     }
@@ -602,14 +600,12 @@
   },
   {
     "context": "MessageEditor > Editor",
-    "use_key_equivalents": true,
     "bindings": {
       "enter": "assistant2::Chat"
     }
   },
   {
     "context": "ContextStrip",
-    "use_key_equivalents": true,
     "bindings": {
       "up": "assistant2::FocusUp",
       "right": "assistant2::FocusRight",
@@ -702,14 +698,12 @@
   },
   {
     "context": "GitPanel && !CommitEditor",
-    "use_key_equivalents": true,
     "bindings": {
       "escape": "git_panel::Close"
     }
   },
   {
     "context": "GitPanel && ChangesList",
-    "use_key_equivalents": true,
     "bindings": {
       "up": "menu::SelectPrev",
       "down": "menu::SelectNext",
@@ -721,7 +715,6 @@
   },
   {
     "context": "GitPanel && CommitEditor > Editor",
-    "use_key_equivalents": true,
     "bindings": {
       "escape": "git_panel::FocusChanges",
       "ctrl-enter": "git::CommitChanges",
@@ -833,7 +826,6 @@
   },
   {
     "context": "ZedPredictModal",
-    "use_key_equivalents": true,
     "bindings": {
       "escape": "menu::Cancel"
     }