[SR] Allow using control + shift + arrow keys for NVDA

[nishasy]

Summary:

NVDA takes control of inputs in its default mode, so users can't use just the arrow keys to move the interactive elements on the graph. We want to allow using modifier key + control + shift + arrow keys to move interactive elements on the graph.

Note: This already works with the modifier key + shift + arrow keys (no control), but holding down shift makes it so that the amount the element moves is 4x more than without shift.

Note 2: When using NVDA, you can get the same keyboard experience as not using a screen reader (i.e. move the points with arrow keys only) if you go into focus mode (NVDA key + space bar).

Implemented:

• Added support for the control key press
  • stops shift from increasing the move difference if control is held down
• Added "modifier key + control + shift +" to the instruction strings

Issue: https://khanacademy.atlassian.net/browse/LEMS-2874

Test plan:

yarn jest packages/perseus/src/widgets/interactive-graphs/interactive-graph.test.tsx

Storybook
http://localhost:6006/?path=/docs/perseuseditor-widgets-interactive-graph--docs

[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (0ca8f4c) and published it to npm. You
can install it using the tag PR2257.

Example:

pnpm add @khanacademy/perseus@PR2257

If you are working in Khan Academy's webapp, you can run:

./dev/tools/bump_perseus_version.sh -t PR2257

[github-actions]

Size Change: +32 B (0%)

Total Size: 872 kB

Filename	Size	Change
packages/perseus/dist/es/index.js	367 kB	+9 B (0%)
packages/perseus/dist/es/strings.js	6.76 kB	+23 B (+0.34%)

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	39.5 kB
packages/keypad-context/dist/es/index.js	760 B
packages/kmath/dist/es/index.js	11.1 kB
packages/math-input/dist/es/index.js	78.2 kB
packages/math-input/dist/es/strings.js	1.79 kB
packages/perseus-core/dist/es/index.js	29.8 kB
packages/perseus-editor/dist/es/index.js	276 kB
packages/perseus-linter/dist/es/index.js	22.8 kB
packages/perseus-score/dist/es/index.js	20.6 kB
packages/pure-markdown/dist/es/index.js	4.14 kB
packages/simple-markdown/dist/es/index.js	13.1 kB

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