Fix schema override

[acwhite211]

Fixes #7682

This fix addresses two root causes in schema config override application: first, update_schema_config.py now preserves explicit ishidden overrides from config/<discipline>/schema_overrides.json during migration-time hide/unhide passes, including applying the explicit true/false value when rerun, so fields like collectionobjectgroupjoin.text1/text2 in Geology are no longer accidentally re-hidden; second, the Splocaleitemstr write path was changed from effectively insert-only behavior to true upsert behavior keyed by language + FK (itemname/itemdesc/containername/containerdesc), which updates existing caption/description text and removes duplicates instead of leaving stale values like Text1. Finally, run_key_migration_functions.fix_schema_config was updated to reapply schema defaults/overrides across all disciplines, ensuring existing databases get corrected without manual row edits.

Checklist

• Self-review the PR after opening it to make sure the changes look good and
  self-explanatory (or properly documented)
• Add relevant issue to release milestone
• Add pr to documentation list
• Add automated tests
• Add a reverse migration if a migration is present in the PR

Testing instructions

• Startup Specify on a blank database and use the setup tool to create a Geography database.
• See that the database setup process runs without errors.
• See the the collectionobjectgroupjoin table has it's field text and descriptions properly set based on the geology schema_overrides file

  specify7/config/geology/schema_overrides.json

  Lines 71 to 81 in 5789550

  	"collectionobjectgroupjoin": {
  	"items": [
  	{ "isprimary": { "ishidden": false, "name": "Is Primary", "desc": "Indicates whether a particular collection object within a group is the primary member." } },
  	{ "issubstrate": { "ishidden": false, "name": "Is Substrate", "desc": "Indicates whether a particular collection object within a group is the substrate that represents the group." } },
  	{ "precedence": { "ishidden": false, "name": "Precedence", "desc": "Determines the order of group members when displayed." } },
  	{ "text1": { "ishidden": false, "name": "Proportion", "desc": "Qualitative or quantitative fraction of a whole for part/whole relationships." } },
  	{ "text2": { "ishidden": false, "name": "Role", "desc": "Role this object plays in the Collection Object Group." } },
  	{ "childco": { "ishidden": false, "name": "Child Collection Object", "desc": "Represents a collection object member of a group." } },
  	{ "childcog": { "ishidden": false, "name": "Child Collection Object Group", "desc": "Represents a collection object group member of a group." } }
  	]
  	},

[grantfitzsimmons]

Strictly UX review:

• Startup Specify on a blank database and use the setup tool to create a Geography database.

I also added new disciplines to an existing database.

• See that the database setup process runs without errors.
• See the the collectionobjectgroupjoin table has it's field text and descriptions properly set based on the geology schema_overrides file

  specify7/config/geology/schema_overrides.json

  Lines 71 to 81 in 5789550

  	"collectionobjectgroupjoin": {
  	"items": [
  	{ "isprimary": { "ishidden": false, "name": "Is Primary", "desc": "Indicates whether a particular collection object within a group is the primary member." } },
  	{ "issubstrate": { "ishidden": false, "name": "Is Substrate", "desc": "Indicates whether a particular collection object within a group is the substrate that represents the group." } },
  	{ "precedence": { "ishidden": false, "name": "Precedence", "desc": "Determines the order of group members when displayed." } },
  	{ "text1": { "ishidden": false, "name": "Proportion", "desc": "Qualitative or quantitative fraction of a whole for part/whole relationships." } },
  	{ "text2": { "ishidden": false, "name": "Role", "desc": "Role this object plays in the Collection Object Group." } },
  	{ "childco": { "ishidden": false, "name": "Child Collection Object", "desc": "Represents a collection object member of a group." } },
  	{ "childcog": { "ishidden": false, "name": "Child Collection Object Group", "desc": "Represents a collection object group member of a group." } }
  	]
  	},