i18n: localize the editor toolbar in all 23 locales

The rich-text editor was the last hardcoded-English surface in the
composer: 21 tooltip titles, the eight table-menu entries, the "Remove
color" entry and the table size picker's "Pick size" label were plain
strings while every other menu in the app is localized.

All of them now come from a new email_composer.toolbar namespace,
translated into all 23 locales using each platform's established
editor terminology (Word/Docs conventions - de "Formatierung löschen",
ar "مسح التنسيق", ja "書式をクリア", ...). The link prompt stays "URL",
which is the same term in every language.

Tooltips and self-sizing dropdowns have no width constraints, so longer
translations are safe everywhere.

locales/lv/common.json

@@ -686,6 +686,38 @@
     "recipient_name_placeholder": "Parādāmais vārds",
     "autocomplete_search_server": "Meklēt serverī",
     "autocomplete_searching": "Meklē...",
+    "toolbar": {
+      "bold": "Treknraksts",
+      "italic": "Kursīvs",
+      "underline": "Pasvītrots",
+      "strikethrough": "Pārsvītrots",
+      "text_color": "Teksta krāsa",
+      "remove_color": "Noņemt krāsu",
+      "heading_1": "Virsraksts 1",
+      "heading_2": "Virsraksts 2",
+      "bullet_list": "Aizzīmju saraksts",
+      "ordered_list": "Numurēts saraksts",
+      "quote": "Citāts",
+      "code_block": "Koda bloks",
+      "align_left": "Līdzināt pa kreisi",
+      "align_center": "Centrēt",
+      "align_right": "Līdzināt pa labi",
+      "text_direction": "Teksta virziens (RTL/LTR)",
+      "link": "Saite",
+      "table": "Tabula",
+      "clear_formatting": "Notīrīt formatējumu",
+      "undo": "Atsaukt",
+      "redo": "Atkārtot",
+      "add_row_above": "Pievienot rindu virs",
+      "add_row_below": "Pievienot rindu zem",
+      "add_column_before": "Pievienot kolonnu pirms",
+      "add_column_after": "Pievienot kolonnu pēc",
+      "delete_row": "Dzēst rindu",
+      "delete_column": "Dzēst kolonnu",
+      "toggle_header_row": "Pārslēgt galvenes rindu",
+      "delete_table": "Dzēst tabulu",
+      "pick_size": "Izvēlēties izmēru"
+    },
     "send_filing_warning": "Nosūtīts - bet pēcapstrāde neizdevās, var palikt novecojis melnraksts."
   },
   "confirm_dialog": {