[Manage] Bump to Backstage 1.48 with necessary fixes

[grantila]

Hey, I just made a Pull Request!

This bumps the Manage plugin to 1.48 and unlocks @backstage/ui from ^.10 to align with the rest of the backstage versions.

@backstage/ui has breaking changes in styling and core backstage has moved some blueprints to -react

✔️ Checklist

• A changeset describing the change and affected packages. (more info)
• Added or updated documentation
• Tests for new functionality and regression tests for bug fixes
• Screenshots attached (for UI changes)
• All your commits have a Signed-off-by line in the message. (more info)

[backstage-goalie]

Changed Packages

Package Name	Package Path	Changeset Bump	Current Version
app-next	workspaces/manage/packages/app-next	none	v0.0.7
app	workspaces/manage/packages/app	none	v0.0.11
backend	workspaces/manage/packages/backend	none	v0.0.11
@backstage-community/plugin-manage-module-tech-insights	workspaces/manage/plugins/manage-module-tech-insights	minor	v0.6.0
@backstage-community/plugin-manage-react	workspaces/manage/plugins/manage-react	minor	v2.0.0
@backstage-community/plugin-manage	workspaces/manage/plugins/manage	minor	v1.0.0

[grantila]

For reviewing, I'd suggest going through commit by commit - they're relatively small individually, and separated in what they do 🙏